allow adbd setpcap

adbd uses setpcap to drop capabilities from the bounding
set on user builds. See system/core commit
080427e4e2b1b72718b660e16b6cf38b3a3c4e3f

Change-Id: I6aec8d321b8210ea50a56aeee9bc94738514beab

adbd.te

@@ -12,6 +12,9 @@ allow adbd shell:process noatsecure;
 # Set UID and GID to shell.  Set supplementary groups.
 allow adbd self:capability { setuid setgid };
 
+# Drop capabilities from bounding set on user builds.
+allow adbd self:capability setpcap;
+
 # Create and use network sockets.
 net_domain(adbd)