pxa2xx PCMCIA timing issue on iPAQ H5550

Recently I've been trying to get working PCMCIA interface on H5000 ipaq
series, using dual PCMCIA sleeve.  So far things work correctly, but I had
to do one modification to drivers/pcmcia/pxa2xx_base.c to get the interface
working with orinoco gold PCMCIA card (wired pcnet_cs ethernet card worked
even without this modification).

The issue has something to do with assert time on PCMCIA bus, but I'm not
really sure what -- I found the working value just by trial&error approach.
 I'm not sure how is the assert value in pxa2xx_mcxx_asst calculated (I
know, simple formula, but the reason why is it calculated that way is not
obvious for me), neither that my modification is correct.  It just works
with iPAQ.

Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>