pcmcia: split up central event handler

Split up the central event handler for 16bit cards into three individual
functions.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

diff --cc drivers/pcmcia/cs.c
Simple merge

diff --cc drivers/pcmcia/cs_internal.h
Simple merge

diff --cc drivers/pcmcia/ds.c
Simple merge