PCMCIA: soc_common: push socket probe down into SoC specific support

Move the individual socket probing and initialization down into the
SoC specific support files, thereby allowing soc_common_drv_pcmcia_probe
to be eliminated.  soc_common.c now no longer deals with distinct groups
of sockets.

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