rfkill: Fix device type check when toggling states

rfkill_switch_all() is supposed to only switch all the interfaces of a
given type, but does not actually do this; instead, it just switches
everything currently in the same state.

Add the necessary type check in.

(This fixes a bug I've been seeing while developing an rfkill laptop
driver, with both bluetooth and wireless simultaneously changing state
after only pressing either KEY_WLAN or KEY_BLUETOOTH).

Signed-off-by: Carlos Corbacho <carlos@strangeworlds.co.uk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>