pcmcia: sa1111: fix propagation of lowlevel board init return code

When testing Lubbock, it was noticed that the sa1111 pcmcia driver bound
but was not functional due to no sockets being registered.  This is
because the return code from the lowlevel board initialisation was not
being propagated out of the probe function.  Fix this.

Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>