PCMCIA: soc_common: remove explicit wrprot initialization in socket drivers

soc_common already initializes state.wrprot to zero, so explicitly
setting wrprot to zero in the socket drivers has no additional effect.

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