In case of error, the function devm_ioremap() returns NULL pointer
not ERR_PTR(). The IS_ERR() test in the return value check should be
replaced with NULL test.
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>