network: enable UDP socket monitoring

network: enable UDP socket monitoring

PD#167119: network: enable UDP socket monitoring

this is need by VtsKernelNetTests, otherwise some test cases will fail

Error info:

testUdp (sock_diag_test.SockDestroyPermissionTest) ... skipped 'INET_UDP_DIAG not enabled'
testClosesUdpSockets (sock_diag_test.SockDestroyUdpTest) ... skipped 'INET_UDP_DIAG not enabled'
testReadInterrupted (sock_diag_test.SockDestroyUdpTest)
Tests that read() is interrupted by SOCK_DESTROY. ... skipped 'INET_UDP_DIAG not enabled'
testSocketAddressesAfterClose (sock_diag_test.SockDestroyUdpTest) ... skipped 'INET_UDP_DIAG not enabled'

Change-Id: I732f8d654a476614308992c756d5c8a8711bbbc9
Signed-off-by: Yixun Lan <yixun.lan@amlogic.com>