asus-nb-wmi: Add wapf4 quirk for the X550VB

X550VB as many others Asus laptops need wapf4 quirk to make RFKILL
switch be functional. Otherwise system boots with wireless card
disabled and is only possible to enable it by suspend/resume.

Bug report:
http://bugzilla.redhat.com/show_bug.cgi?id=1089731#c23



Reported-and-tested-by: Vratislav Podzimek <vpodzime@redhat.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>