drm/amdgpu: move some atombios definitions to common folder (v2)

the definitions can be shared by different IP components.

v2: fix include path

Signed-off-by: Jammy Zhou <Jammy.Zhou@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/Makefile b/drivers/gpu/drm/amd/amdgpu/Makefile
index ccdbb35..733f775 100644
--- a/drivers/gpu/drm/amd/amdgpu/Makefile
+++ b/drivers/gpu/drm/amd/amdgpu/Makefile
@@ -3,7 +3,8 @@
 # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
 
 ccflags-y := -Iinclude/drm -Idrivers/gpu/drm/amd/include/asic_reg \
-	-Idrivers/gpu/drm/amd/include
+	-Idrivers/gpu/drm/amd/include \
+	-Idrivers/gpu/drm/amd/amdgpu
 
 amdgpu-y := amdgpu_drv.o