PCMCIA: sa1111: pass along sa1111_pcmcia_configure_socket() failure code

Pass along the sa1111_pcmcia_configure_socket() failure code to
higher levels, rather than just returning zero.

Acked-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>