USB: ohci-sm501: Add missed iounmap() in remove

This driver misses calling iounmap() in remove to undo the ioremap()
called in probe.
Add the missed call to fix it.

Fixes: f54aab6e ("usb: ohci-sm501 driver")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20200610024844.3628408-1-hslester96@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>