Revert "wl1251: enforce changed hw encryption support on monitor state change"

This reverts commit 1c0a933c25ed0c5a2a78c3f04d9c0622c7243f10.

This commit (or rather, hack) breaks ad-hoc mode. Steps to reproduce:
ifconfig wlan0 down
iwconfig wlan0 mode ad-hoc
ifconfig wlan0 up
[  209.124298] ------------[ cut here ]------------
[  209.129333] kernel BUG at kernel/workqueue.c:1060!
[  209.134460] Internal error: Oops - undefined instruction: 0 [#1]
...
[  209.391571] [<c0052d4c>] (__queue_work+0x144/0x270) from [<c0052ec4>]
[  209.400878] [<c0052ec4>] (queue_work_on+0x30/0x38) from [<c0052ef8>]
[  209.409851] [<c0052ef8>] (queue_work+0x18/0x1c) from [<bf1aaaf4>]
[  209.420135] [<bf1aaaf4>] (wl1251_op_config+0x160/0x260 [wl1251])
...