commit 6734330654dac550f12e932996b868c6d0dcb421 upstream.

In case ioremap fails, the fix returns -ENOMEM to avoid NULL
pointer dereferences.
Multiple places use port.membase.
Signed-off-by: NKangjie Lu <kjlu@umn.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>