hp-wmi: improve rfkill support

1) Add support for reading the hardware blocked state.  Previously
   we read a combination of the hardware and software blocked states,
   reporting it as the software blocked state.  This caused some
   confusing behaviour.

2) The software state is persistent, mark it as such.

3) Check rfkill in the resume handler.  Both the hard and soft
   blocked states may change over hibernation.

Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Acked-by: Matthew Garrett <mjg@redhat.com>
Tested-by: Maciej Rutecki <maciej.rutecki@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>