intel: Don't dereference a NULL pointer of calloc fails

The caller of NewTextureObject does the right thing if NULL is returned,
so this function should do the right thing too.

NOTE: This is a candidate for stable branches.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
(cherry picked from commit 505ac6ddc6)

src/mesa/drivers/dri/intel/intel_tex.c

@@ -34,6 +34,10 @@ intelNewTextureObject(struct gl_context * ctx, GLuint name, GLenum target)
    (void) ctx;
 
    DBG("%s\n", __FUNCTION__);
+
+   if (obj == NULL)
+      return NULL;
+
    _mesa_initialize_texture_object(&obj->base, name, target);
 
    obj->needs_validate = true;