Add rtl8180 wireless driver

This patch adds a mac80211 based wireless driver for the rtl8180 and
rtl8185 PCI wireless cards.  Also included are some rtl8187 changes
required due to the relationship between that driver and this one.

Michael Wu is primarily responsible for the initial driver and rtl8185
support.  Andreas Merello provided the additional rtl8180 support.

Thanks to Jukka Ruohonen for the donating a rtl8185 card! It was very
helpful for the rtl8225z2 code.

The Signed-off-by information below is collected from the individual
patches submitted to wireless-2.6 before merging this driver upstream.

Signed-off-by: Andrea Merello <andreamrl@tiscali.it>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>