net: fujitsu: fix potential null-ptr-deref

In fmvj18x_get_hwinfo(), if ioremap fails there will be NULL pointer
deref. To fix this, check the return value of ioremap and return -1
to the caller in case of failure.

Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com>
Link: https://lore.kernel.org/r/20210503115736.2104747-16-gregkh@linuxfoundation.org


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