[PATCH] ipw2200: Bluetooth coexistence support

I've added a new module param "bt_coexist" which defaults to OFF.

This does not seem to fix the firmware restarts, but it does do "the
right thing" and disables something that we were enabling by default:
signaling the Bluetooth h/w which channel we're on (whether or not the
BT h/w was out there).

Signed-off-by: Ben M Cahill <ben.m.cahill@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>