Add some information useful for PCMCIA device driver authors to
Documentation/pcmcia/, and reference it in dmesg in case of hash mismatches.

Also add a reference to pcmciautils to Documentation/Changes.  With recent
changes, you don't need to concern yourself with pcmcia-cs even if you have
PCMCIA hardware, so the example above the list needed to be adapted as well.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowksi.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>