drm/exynos: remove incorrect ccflags from Makefile

Include directories are provided by core already, adding them in driver
is redundand and causes warnings in case of out-of-tree build.

v2:
- fixed include in exynos_drm_iommu.c
- typo in commit message

Signed-off-by: Andrzej Hajda <[e-mail]>
Signed-off-by: Inki Dae <[e-mail]>

drivers/gpu/drm/exynos/Makefile

···
 # Makefile for the drm device driver.  This driver provides support for the
 # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
 
-ccflags-y := -Iinclude/drm -Idrivers/gpu/drm/exynos
 exynosdrm-y := exynos_drm_drv.o exynos_drm_crtc.o exynos_drm_fbdev.o \
 		exynos_drm_fb.o exynos_drm_gem.o exynos_drm_core.o \
 		exynos_drm_plane.o

drivers/gpu/drm/exynos/exynos_drm_iommu.c

···
  * option) any later version.
  */
 
-#include <drmP.h>
+#include <drm/drmP.h>
 #include <drm/exynos_drm.h>
 
 #include <linux/dma-mapping.h>

drivers/gpu/drm/exynos/exynos_drm_rotator.c

···
 #include <drm/drmP.h>
 #include <drm/exynos_drm.h>
 #include "regs-rotator.h"
-#include "exynos_drm.h"
 #include "exynos_drm_drv.h"
 #include "exynos_drm_ipp.h"