drm/radeon/kms: detect sideport memory on IGP chips

This detects if the sideport memory is enabled and
if it is VRAM is evicted on suspend/resume.

This should fix s/r issues on some IGPs.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 53b5560..a7e349d 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -319,10 +319,12 @@
 	u64			real_vram_size;
 	int			vram_mtrr;
 	bool			vram_is_ddr;
+	bool                    igp_sideport_enabled;
 };
 
 int radeon_mc_setup(struct radeon_device *rdev);
-
+bool radeon_combios_sideport_present(struct radeon_device *rdev);
+bool radeon_atombios_sideport_present(struct radeon_device *rdev);
 
 /*
  * GPU scratch registers structures, functions & helpers