drm/amd: drop use of drmP.h in atom.h

Drop use of the deprecated drmP.h header from atom.h

Fix fallout in various files.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190609220757.10862-6-sam@ravnborg.org

drivers/gpu/drm/amd/amdgpu/atom.h

@@ -26,7 +26,8 @@
 #define ATOM_H
 
 #include <linux/types.h>
-#include <drm/drmP.h>
+
+struct drm_device;
 
 #define ATOM_BIOS_MAGIC		0xAA55
 #define ATOM_ATI_MAGIC_PTR	0x30