drm/pl111: Make sure of_device_id tables are NULL terminated

We prefer to of_device_id tables are NULL terminated. So make
vexpress_muxfpga_match is NULL terminated.

Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1533379767-15629-1-git-send-email-zhongjiang@huawei.com


Signed-off-by: Sean Paul <seanpaul@chromium.org>