drm: atomic helper: fix W=1 warnings

Few for_each macro set variables that are never used later which led
to generate unused-but-set-variable warnings.
Add (void)(foo) inside the macros to remove these warnings
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20191008124254.2144-1-benjamin.gaignard@st.com

include/drm/drm_atomic.h

@@ -693,6 +693,7 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
 	     (__i)++)								\
 		for_each_if ((__state)->connectors[__i].ptr &&			\
 			     ((connector) = (__state)->connectors[__i].ptr,	\
+			     (void)(connector) /* Only to avoid unused-but-set-variable warning */, \
 			     (old_connector_state) = (__state)->connectors[__i].old_state,	\
 			     (new_connector_state) = (__state)->connectors[__i].new_state, 1))
 
@@ -714,6 +715,7 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
 	     (__i)++)								\
 		for_each_if ((__state)->connectors[__i].ptr &&			\
 			     ((connector) = (__state)->connectors[__i].ptr,	\
+			     (void)(connector) /* Only to avoid unused-but-set-variable warning */, \
 			     (old_connector_state) = (__state)->connectors[__i].old_state, 1))
 
 /**
@@ -734,7 +736,9 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
 	     (__i)++)								\
 		for_each_if ((__state)->connectors[__i].ptr &&			\
 			     ((connector) = (__state)->connectors[__i].ptr,	\
-			     (new_connector_state) = (__state)->connectors[__i].new_state, 1))
+			     (void)(connector) /* Only to avoid unused-but-set-variable warning */, \
+			     (new_connector_state) = (__state)->connectors[__i].new_state, \
+			     (void)(new_connector_state) /* Only to avoid unused-but-set-variable warning */, 1))
 
 /**
  * for_each_oldnew_crtc_in_state - iterate over all CRTCs in an atomic update
@@ -754,7 +758,9 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
 	     (__i)++)							\
 		for_each_if ((__state)->crtcs[__i].ptr &&		\
 			     ((crtc) = (__state)->crtcs[__i].ptr,	\
+			      (void)(crtc) /* Only to avoid unused-but-set-variable warning */, \
 			     (old_crtc_state) = (__state)->crtcs[__i].old_state, \
+			     (void)(old_crtc_state) /* Only to avoid unused-but-set-variable warning */, \
 			     (new_crtc_state) = (__state)->crtcs[__i].new_state, 1))
 
 /**
@@ -793,7 +799,9 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
 	     (__i)++)							\
 		for_each_if ((__state)->crtcs[__i].ptr &&		\
 			     ((crtc) = (__state)->crtcs[__i].ptr,	\
-			     (new_crtc_state) = (__state)->crtcs[__i].new_state, 1))
+			     (void)(crtc) /* Only to avoid unused-but-set-variable warning */, \
+			     (new_crtc_state) = (__state)->crtcs[__i].new_state, \
+			     (void)(new_crtc_state) /* Only to avoid unused-but-set-variable warning */, 1))
 
 /**
  * for_each_oldnew_plane_in_state - iterate over all planes in an atomic update
@@ -813,6 +821,7 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
 	     (__i)++)							\
 		for_each_if ((__state)->planes[__i].ptr &&		\
 			     ((plane) = (__state)->planes[__i].ptr,	\
+			      (void)(plane) /* Only to avoid unused-but-set-variable warning */, \
 			      (old_plane_state) = (__state)->planes[__i].old_state,\
 			      (new_plane_state) = (__state)->planes[__i].new_state, 1))
 
@@ -873,7 +882,9 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
 	     (__i)++)							\
 		for_each_if ((__state)->planes[__i].ptr &&		\
 			     ((plane) = (__state)->planes[__i].ptr,	\
-			      (new_plane_state) = (__state)->planes[__i].new_state, 1))
+			      (void)(plane) /* Only to avoid unused-but-set-variable warning */, \
+			      (new_plane_state) = (__state)->planes[__i].new_state, \
+			      (void)(new_plane_state) /* Only to avoid unused-but-set-variable warning */, 1))
 
 /**
  * for_each_oldnew_private_obj_in_state - iterate over all private objects in an atomic update