rfkill: allow use of multiple arguments

rfkill: allow use of multiple arguments

There is no reason why multiple arguments could not be supported.

Most common use case is to do multiple control commands in one go without us
of 'all' argument that can cause unnecessary connection breakage.  For
example someone might want to add to a system initialization following
commands.

    rfkill block bluetooth uwb wimax wwan gps fm nfc

That will ensure everything but wifi is turned off with as few commands as
possible, without killing wifi at any point.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>