clover: return CL_INVALID_VALUE when origin or region are NULL

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9212>

src/gallium/frontends/clover/api/transfer.cpp

@@ -36,6 +36,8 @@ namespace {
 
    vector_t
    vector(const size_t *p) {
+      if (!p)
+         throw error(CL_INVALID_VALUE);
       return range(p, 3);
    }