intel/blorp: Fix possible NULL pointer dereferencing

Fix incomplete check of input params in blorp_surf_convert_to_uncompressed()
which can lead to NULL pointer dereferencing.

Fixes: 5ae8043fed ("intel/blorp: Add an entrypoint for doing
bit-for-bit copies")
Fixes: f395d0abc8 ("intel/blorp: Internally expose
surf_convert_to_uncompressed")
Reviewed-by: Emil Velikov <emli.velikov@collabora.com>
Reviewed-by: Andres Gomez <agomez@igalia.com>

src/intel/blorp/blorp_blit.c

@@ -2351,7 +2351,7 @@ blorp_surf_convert_to_uncompressed(const struct isl_device *isl_dev,
     */
    blorp_surf_convert_to_single_slice(isl_dev, info);
 
-   if (width || height) {
+   if (width && height) {
 #ifndef NDEBUG
       uint32_t right_edge_px = info->tile_x_sa + *x + *width;
       uint32_t bottom_edge_px = info->tile_y_sa + *y + *height;
@@ -2364,7 +2364,7 @@ blorp_surf_convert_to_uncompressed(const struct isl_device *isl_dev,
       *height = DIV_ROUND_UP(*height, fmtl->bh);
    }
 
-   if (x || y) {
+   if (x && y) {
       assert(*x % fmtl->bw == 0);
       assert(*y % fmtl->bh == 0);
       *x /= fmtl->bw;