rtlwifi: kfree entry until after entry->bssid has been accessed

The current code kfree's entry and then dereferences it by accessing
entry->bssid.  Avoid the dereference-after-free by moving the kfree
after the access to entry->bssid.

Detected by CoverityScan, CID#1448600 ("Read from pointer after free")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>