wifi: rtw89: Fix some error handling path in rtw89_wow_enable()

'ret' is not updated after several function calls in rtw89_wow_enable().
This prevent error handling from working.

Add the missing assignments.

Fixes: 19e28c7f ("wifi: rtw89: add WoWLAN function support")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/32320176eeff1c635baeea25ef0e87d116859e65.1668354083.git.christophe.jaillet@wanadoo.fr