parisc: Check the return value of ioremap() in lba_driver_probe()

The function ioremap() in lba_driver_probe() can fail, so
its return value should be checked.

Fixes: 4bdc0d67

 ("remove ioremap_nocache and devm_ioremap_nocache")
Reported-by: Hacash Robot <hacashRobot@santino.com>
Signed-off-by: William Dean <williamsukatube@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.6+