bssgp_vty: Remove dead code and compiler warning

gprs_bssgp_vty.c:48:34: warning: ‘gprs_bssgp_timer_strs’ defined but not used [-Wunused-const-variable=]
 static const struct value_string gprs_bssgp_timer_strs[] = {
                                  ^~~~~~~~~~~~~~~~~~~~~

Change-Id: Ia41ccb7b227c41996cdef51dc6779bfc5b5a8d48
1 file changed