reset: uniphier-glue: Fix possible null-ptr-deref

reset: uniphier-glue: Fix possible null-ptr-deref

[ Upstream commit 3a2390c6777e3f6662980c6cfc25cafe9e4fef98 ]

It will cause null-ptr-deref when resource_size(res) invoked,
if platform_get_resource() returns NULL.

Fixes: d3afeb219515 ("reset: uniphier: add USB3 core reset control")
Signed-off-by: Hui Tang <tanghui20@huawei.com>
Reviewed-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Link: https://lore.kernel.org/r/20221114004958.258513-1-tanghui20@huawei.com
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>