r600g: avoid unneeded bo wait

if we know the bo has gone not busy, no need to add another bo wait

thanks to Andre (taiu) on irc for pointing this out.

src/gallium/winsys/r600/drm/radeon_bo_pb.c

@@ -100,6 +100,10 @@ radeon_bo_pb_map_internal(struct pb_buffer *_buf,
 		uint32_t domain;
 		if (radeon_bo_busy(buf->mgr->radeon, buf->bo, &domain))
 			return NULL;
+		if (radeon_bo_map(buf->mgr->radeon, buf->bo)) {
+			return NULL;
+		}
+		goto out;
 	}
 
 	if (buf->bo->data != NULL) {
@@ -115,7 +119,7 @@ radeon_bo_pb_map_internal(struct pb_buffer *_buf,
 			return NULL;
 		}
 	}
-
+out:
 	LIST_DELINIT(&buf->maplist);
 	return buf->bo->data;
 }