drivers: counter: cat1: Fix test_single_shot_alarm_notop

TC "test_single_shot_alarm_notop" is failing because there were 2 ISR
callbacks instead of one. this is because of invoking
ifx_cat1_counter_set_int_pending incorrectly. Updated
ifx_cat1_counter_set_alarm to fix this

Signed-off-by: Sreeram Tatapudi <sreeram.praveen@infineon.com>