This function doesn't use uclass_find_first_device() correctly. Add a
check that the device is found so we don't try to read properties from a
NULL device.
The fixes booting on minnoxmax.
Fixes: 87f1084a63 ("x86: Adjust mrccache_get_region() to use livetree")
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>