wpa: Add permissions for hwbinder

Modify permissions for wpa_supplicant to use hwbinder (for HIDL),
instead of binder.

Denials:
01-15 14:31:58.573   541   541 W wpa_supplicant: type=1400
audit(0.0:10): avc: denied { call } for scontext=u:r:wpa:s0
tcontext=u:r:hwservicemanager:s0 tclass=binder permissive=0
01-15 14:31:58.573   541   541 W wpa_supplicant: type=1400
audit(0.0:11): avc: denied { call } for scontext=u:r:wpa:s0
tcontext=u:r:hwservicemanager:s0 tclass=binder permissive=0

BUG: 31365276
Test: Compiled and ensured that the selinux denials are no longer
present in logs.

Change-Id: Ifa4630edea6ec5a916b3940f9a03ef9dc6fc9af2