drm/exynos: remove unused wait_for macro

This is a leftover, all code using this macro have been removed/
changed already.
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_drv.h

@@ -23,20 +23,6 @@
 #define MAX_FB_BUFFER	4
 #define DEFAULT_ZPOS	-1
 
-#define _wait_for(COND, MS) ({ \
-	unsigned long timeout__ = jiffies + msecs_to_jiffies(MS);	\
-	int ret__ = 0;							\
-	while (!(COND)) {						\
-		if (time_after(jiffies, timeout__)) {			\
-			ret__ = -ETIMEDOUT;				\
-			break;						\
-		}							\
-	}								\
-	ret__;								\
-})
-
-#define wait_for(COND, MS) _wait_for(COND, MS)
-
 /* This enumerates device type. */
 enum exynos_drm_device_type {
 	EXYNOS_DEVICE_TYPE_NONE,