btlinux: Add SYS_NICE to btlinux service

commit bf3995a5907a4621a220c5b11b56a7e0adbbd220 aosp.

btlinux service is trying to set SCHED_FIFO policy and fails:
android.hardware.bluetooth@1.1-service.btlinux: ThreadRoutine unable to
set SCHED_FIFO for pid 385, tid 1191, error Operation not permitted

Bug: 208308923
Test: adb logcat | grep SCHED_FIFO

Signed-off-by: hmz007 <hmz007@gmail.com>

system/bt/vendor_libs/linux/interface/android.hardware.bluetooth@1.1-service.btlinux.rc

@@ -2,4 +2,4 @@ service btlinux-1.1 /vendor/bin/hw/android.hardware.bluetooth@1.1-service.btlinu
     class hal
     user bluetooth
     group bluetooth net_admin net_bt_admin
-    capabilities NET_ADMIN
+    capabilities NET_ADMIN SYS_NICE