mmc: host: omap_hsmmc: checking for NULL instead of IS_ERR()

mmc: host: omap_hsmmc: checking for NULL instead of IS_ERR()

[ Upstream commit ec5ab8933772c87f24ad62a4a602fe8949f423c2 ]

devm_pinctrl_get() returns error pointers, it never returns NULL.

Fixes: 455e5cd6f736 ("mmc: omap_hsmmc: Pin remux workaround to support SDIO interrupt on AM335x")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>