wifi: ath11k: drop redundant check in ath11k_dp_rx_mon_dest_process()

wifi: ath11k: drop redundant check in ath11k_dp_rx_mon_dest_process()

In 'ath11k_dp_rx_mon_dest_process()', 'mon_dst_srng' points to
a member of 'srng_list', which is a fixed-size array inside
'struct ath11k_hal'. This way, if 'ring_id' is valid (i. e.
between 0 and HAL_SRNG_RING_ID_MAX - 1 inclusive), 'mon_dst_srng'
can't be NULL and so relevant check may be dropped.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230824075121.121144-1-dmantipov@yandex.ru