sony-laptop: re-read the rfkill state when resuming from suspend

Without this, the hard-blocked state will be reported incorrectly if
the hardware switch is changed while the laptop is suspended.

Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Tested-by: Norbert Preining <preining@logic.at>
Acked-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: John W. Linville <linville@tuxdriver.com>