ssb: Fix PCMCIA lowlevel register access

This fixes lowlevel register access for PCMCIA based devices.

The patch also adds a temporary workaround for the device mac address.
It simply adds generation of a random address. The real SPROM extraction
will follow in another patch.
The temporary workaround will be removed then, but for now it's OK.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>