wifi: mwifiex: remove unused evt_buf variable

clang with W=1 reports
drivers/net/wireless/marvell/mwifiex/11h.c:198:6: error: variable
'evt_buf' set but not used [-Werror,-Wunused-but-set-variable]
u8 *evt_buf;
^
This variable is not used so remove it.

Signed-off-by: Tom Rix <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Signed-off-by: Kalle Valo <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/net/wireless/marvell/mwifiex/11h.c

···
 {
 	struct host_cmd_ds_chan_rpt_event *rpt_event;
 	struct mwifiex_ie_types_chan_rpt_data *rpt;
-	u8 *evt_buf;
 	u16 event_len, tlv_len;
 
 	rpt_event = (void *)(skb->data + sizeof(u32));
···
 			    "Error in channel report event\n");
 		return -1;
 	}
-
-	evt_buf = (void *)&rpt_event->tlvbuf;
 
 	while (event_len >= sizeof(struct mwifiex_ie_types_header)) {
 		rpt = (void *)&rpt_event->tlvbuf;
···
 			break;
 		}
 
-		evt_buf += (tlv_len + sizeof(rpt->header));
 		event_len -= (tlv_len + sizeof(rpt->header));
 	}