vppinfra: conformed spinlocks to use CLIB_PAUSE

Modified test-and-set spin locks to call CLIB_PAUSE () when spinning
for code consistency. Decreases the memory bandwidth consumed.

Type: fix

Change-Id: I1cca4f87f44f23f257c7a35466cd2e7767072f51
Signed-off-by: Jason Zhang <jason.zhang2@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Lijian Zhang <Lijian.Zhang@arm.com>