drm/amd/display: Include missing header

The file amdgpu_dm_plane.c missed the header amdgpu_dm_plane.h, which
resulted on the following warning:

drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:1046:5:
warning: no previous prototype for 'fill_dc_scaling_info'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:1222:6:
warning: no previous prototype for 'handle_cursor_update'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:152:6:
warning: no previous prototype for 'modifier_has_dcc'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:1576:5:
warning: no previous prototype for 'amdgpu_dm_plane_init'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:157:10:
warning: no previous prototype for 'modifier_gfx9_swizzle_mode'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:752:5:
warning: no previous prototype for 'fill_plane_buffer_attributes'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:83:31:
warning: no previous prototype for 'amd_get_format_info'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:88:6:
warning: no previous prototype for 'fill_blending_from_plane_state'
[-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm_plane.c:992:5:
warning: no previous prototype for 'dm_plane_helper_check_state'
[-Wmissing-prototypes]

Therefore, include the missing header on the file and turn global functions
that are not used outside of the file into static functions.

Fixes: 5d945cbc ("drm/amd/display: Create a file dedicated to planes")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c

@@ -34,6 +34,7 @@
 #include "dal_asic_id.h"
 #include "amdgpu_display.h"
 #include "amdgpu_dm_trace.h"
+#include "amdgpu_dm_plane.h"
 #include "gc/gc_11_0_0_offset.h"
 #include "gc/gc_11_0_0_sh_mask.h"
 
@@ -149,12 +150,12 @@ static void add_modifier(uint64_t **mods, uint64_t *size, uint64_t *cap, uint64_
 	*size += 1;
 }
 
-bool modifier_has_dcc(uint64_t modifier)
+static bool modifier_has_dcc(uint64_t modifier)
 {
 	return IS_AMD_FMT_MOD(modifier) && AMD_FMT_MOD_GET(DCC, modifier);
 }
 
-unsigned modifier_gfx9_swizzle_mode(uint64_t modifier)
+static unsigned modifier_gfx9_swizzle_mode(uint64_t modifier)
 {
 	if (modifier == DRM_FORMAT_MOD_LINEAR)
 		return 0;

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.h

@@ -36,17 +36,9 @@ int fill_dc_scaling_info(struct amdgpu_device *adev,
 			 const struct drm_plane_state *state,
 			 struct dc_scaling_info *scaling_info);
 
-void get_min_max_dc_plane_scaling(struct drm_device *dev,
-				  struct drm_framebuffer *fb,
-				  int *min_downscale, int *max_upscale);
-
 int dm_plane_helper_check_state(struct drm_plane_state *state,
 				struct drm_crtc_state *new_crtc_state);
 
-bool modifier_has_dcc(uint64_t modifier);
-
-unsigned int modifier_gfx9_swizzle_mode(uint64_t modifier);
-
 int fill_plane_buffer_attributes(struct amdgpu_device *adev,
 				 const struct amdgpu_framebuffer *afb,
 				 const enum surface_pixel_format format,