non_plat: Label /dev/ut_keymaster and allow relevant permissions to sources

/dev/ut_keymaster is used by keymaster. Label it and allow relevant permissions
which domains using it (vold, tee and keymaster) requires.

Denial observed without this change:
[   46.666247] .(2)[399:logd.auditd]type=1400 audit(1609128921.744:392): avc: denied { ioctl } for comm="[email protected]" path="/dev/ut_keymaster" dev="tmpfs" ino=17464 ioctlcmd=0x5402 scontext=u:r:hal_keymaster_default:s0 tcontext=u:object_r:device:s0 tclass=chr_file permissive=1

Test: Boot and notice that denial no longer appears

Signed-off-by: Aayush Gupta <[email protected]>
Change-Id: Iee0126d637a139397db8857d8a780277c3ea4576