qcacmn: Create monitor mode spinlock and add null check

Due to changes in datapath init/deinit path, mon_lock spinlock was not
getting created. Create mon_lock spinlock during
dp_rx_pdev_mon_cmn_desc_pool_init.

Add null check to validate rx_tlv_header before calling
hal_rx_mpdu_start_tlv_tag_valid.

Change-Id: I41c781de29f2c8c05ec1bfa90f9c8f742f2539bf
CRs-Fixed: 2693687

hal/wifi3.0/qca6750/hal_6750.c

@@ -1435,6 +1435,24 @@ bool hal_rx_get_fisa_timeout_6750(uint8_t *buf)
 	return HAL_RX_TLV_GET_FISA_TIMEOUT(buf);
 }
 
+/**
+ * hal_rx_mpdu_start_tlv_tag_valid_6750 () - API to check if RX_MPDU_START
+ * tlv tag is valid
+ *
+ *@rx_tlv_hdr: start address of rx_pkt_tlvs
+ *
+ * Return: true if RX_MPDU_START is valied, else false.
+ */
+static uint8_t hal_rx_mpdu_start_tlv_tag_valid_6750(void *rx_tlv_hdr)
+{
+	struct rx_pkt_tlvs *rx_desc = (struct rx_pkt_tlvs *)rx_tlv_hdr;
+	uint32_t tlv_tag;
+
+	tlv_tag = HAL_RX_GET_USER_TLV32_TYPE(&rx_desc->mpdu_start_tlv);
+
+	return tlv_tag == WIFIRX_MPDU_START_E ? true : false;
+}
+
 /**
  * hal_reo_set_err_dst_remap_6750(): Function to set REO error destination
  *				     ring remap register
@@ -1577,7 +1595,7 @@ struct hal_hw_txrx_ops qca6750_hal_hw_txrx_ops = {
 	hal_rx_get_flow_agg_continuation_6750,
 	hal_rx_get_flow_agg_count_6750,
 	hal_rx_get_fisa_timeout_6750,
-	NULL,
+	hal_rx_mpdu_start_tlv_tag_valid_6750,
 	NULL,
 	NULL,