drm/radeon/kms: Fix AGP support for R600/RV770 family (v2)

For AGP to work unmapped access must cover VRAM & AGP as
AGP is treated like VRAM by the GPU (ie physical address).
This patch properly setup the virtual memory system aperture
to cover AGP if AGP is enabled. It seems that there is memory
corruption after resume when using AGP (RV770 seems unaffected
thought). Version 2 just fix merge issue with updated AGP
fallback patch.

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r600d.h b/drivers/gpu/drm/radeon/r600d.h
index 723295f..5084595 100644
--- a/drivers/gpu/drm/radeon/r600d.h
+++ b/drivers/gpu/drm/radeon/r600d.h
@@ -642,6 +642,7 @@
 #define		G_000E50_MCDW_BUSY(x)			(((x) >> 13) & 1)
 #define		G_000E50_SEM_BUSY(x)			(((x) >> 14) & 1)
 #define		G_000E50_RLC_BUSY(x)			(((x) >> 15) & 1)
+#define		G_000E50_BIF_BUSY(x)			(((x) >> 29) & 1)
 #define	R_000E60_SRBM_SOFT_RESET			0x0E60
 #define		S_000E60_SOFT_RESET_BIF(x)		(((x) & 1) << 1)
 #define		S_000E60_SOFT_RESET_CG(x)		(((x) & 1) << 2)