wifi: cw1200: Fix potential memory leak in cw1200_bh_rx_helper()

wifi: cw1200: Fix potential memory leak in cw1200_bh_rx_helper()

[ Upstream commit 5e88e864118c20e63a1571d0ff0a152e5d684959 ]

In one of the error paths, the memory allocated for skb_rx is not freed.
Fix that by freeing it before returning.

Fixes: a910e4a94f69 ("cw1200: add driver for the ST-E CW1100 & CW1200 WLAN chipsets")
Signed-off-by: Abdun Nihaal <nihaal@cse.iitm.ac.in>
Link: https://patch.msgid.link/20251110175316.106591-1-nihaal@cse.iitm.ac.in
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>