drm/ttm: Make ttm_bo_mem_compat available

There are cases where it is desired to see if a proposed placement
is compatible with a buffer object before calling ttm_bo_validate().

Signed-off-by: Sinclair Yeh <syeh@vmware.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Cc: <stable@vger.kernel.org>
---
This is the first of a 3-patch series to fix a black screen
issue observed on Ubuntu 16.04 server.
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 39386f5..a71cf98 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1034,9 +1034,9 @@
 	return ret;
 }
 
-static bool ttm_bo_mem_compat(struct ttm_placement *placement,
-			      struct ttm_mem_reg *mem,
-			      uint32_t *new_flags)
+bool ttm_bo_mem_compat(struct ttm_placement *placement,
+		       struct ttm_mem_reg *mem,
+		       uint32_t *new_flags)
 {
 	int i;
 
@@ -1068,6 +1068,7 @@
 
 	return false;
 }
+EXPORT_SYMBOL(ttm_bo_mem_compat);
 
 int ttm_bo_validate(struct ttm_buffer_object *bo,
 			struct ttm_placement *placement,