pcmcia: clean up dead drivers for CompuLab CM-X255/CM-X270 boards

Commit 9d323914 ("ARM: pxa: remove Compulab pxa2xx boards") removes
the config MACH_ARMCORE in ./arch/arm/mach-pxa/Kconfig.

Hence, ./scripts/checkkconfigsymbols.py warns on non-existing configs:

MACH_ARMCORE
Referencing files: drivers/pcmcia/Kconfig, drivers/pcmcia/Makefile

Clean up the dead remains of pcmcia drivers for Compulab pxa2xx boards.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>