drm/radeon: make VM size a module parameter (v2)

v2: agd5f: simplify patch

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 3c543ef..6f32f16 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -100,6 +100,7 @@
 extern int radeon_aspm;
 extern int radeon_runtime_pm;
 extern int radeon_hard_reset;
+extern int radeon_vm_size;
 
 /*
  * Copy from radeon_drv.h so we don't have to include both and have conflicting