wifi: rtlwifi: rtl8192se: rise completion of firmware loading as last step

Just like in commit 4dfde294 ("rtlwifi: rise completion at the last
step of firmware callback"), only signal completion once the function is
finished. Otherwise, the module removal waiting for the completion could
free the memory that the callback will still use before returning.

Fixes: b0302aba ("rtlwifi: Convert to asynchronous firmware load")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20241107133322.855112-3-cascardo@igalia.com