mwl8k: remove MWL8K_RADIO_* defines

Instead of passing a flag bitmask to mwl8k_cmd_802_11_radio_control,
pass the 'enable' and 'force' arguments as separate parameters, and
introduce wrappers for the common cases of enabling and disabling
without forcing.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>