drm/amd: fix include notation and remove -Iinclude/drm flag

Include <drm/*.h> instead of relative path from include/drm, then
remove the -Iinclude/drm compiler flag.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1493009447-31524-4-git-send-email-yamada.masahiro@socionext.com
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 73e982c..2a4113b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -39,7 +39,7 @@
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
 #include <linux/vga_switcheroo.h>
-#include "drm_crtc_helper.h"
+#include <drm/drm_crtc_helper.h>
 
 #include "amdgpu.h"
 #include "amdgpu_irq.h"