Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

CardBus instead of cardbus.

The TOPIC97 and TOPIC100 seem to have a special register in the exca
space that enables low voltage operation (and maybe other stuff).
Enable the bits in this register so low voltage 16-bit cards may work.

Existance noticed in NetBSD driver.

Start each of the license/copyright comments with /*-, minor shuffle of lines

Add two of three workarounds for interrupt storms for o2micro parts as
obtained from o2micro. These should only be needed for 'older'
o2micro bridges (anything before the 7xxx series of bridges), but will
work with the new bridges.

# I don't plan on porting it to oldcard, but will happily commit to
# oldcard if someone else needs them.

Massive overhaul of exca to help with the isa efforts:
o chip_name arrays ifdef'd out.
o use the OLDCARD-like get/put functions so we can support differnt types
of mappings.
o Write the beggings of is this a valid exca device and introduce more
chipset support.

# this is partially a wip, but also needed because some other cahnges I've
# made require some of these changes.

MFp4:
o Protect .h against multiple includes.
o eliminate the pointers to the read/write routines. The
bus_space_read routines can cope since we have the offset
field.
o Print a warning if the requested map address is > 16M and
your chipset doesn't support the extended ExCA registers.

First draft of common code between pccbb and pcic drivers for talking
to ExCA register sets. These registers exist in both ISA and PCI
devices in a couple different ways, and this will provide a common
base for future building. This code is a rehash of the pccbb 16-bit
code, which was a rehash of the pcic code, which was a rehash of the
netbsd i82365 code. More hashing to come.