drm/radeon: fix a bogus kfree

parser->chunks[.].kpage[.] is not always kmalloc-ed
by the parser initialization, so parser_fini should
not try to kfree it if it didn't allocate it.

This patch fixes a kernel oops that can be provoked
in UMS mode.
Signed-off-by: Ilija Hadzic <ihadzic@research.bell-labs.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/r600_cs.c

@@ -2476,8 +2476,10 @@ static void r600_cs_parser_fini(struct radeon_cs_parser *parser, int error)
 	kfree(parser->relocs);
 	for (i = 0; i < parser->nchunks; i++) {
 		kfree(parser->chunks[i].kdata);
-		kfree(parser->chunks[i].kpage[0]);
-		kfree(parser->chunks[i].kpage[1]);
+		if (parser->rdev && (parser->rdev->flags & RADEON_IS_AGP)) {
+			kfree(parser->chunks[i].kpage[0]);
+			kfree(parser->chunks[i].kpage[1]);
+		}
 	}
 	kfree(parser->chunks);
 	kfree(parser->chunks_array);