wifi-scripts: don't fail on unset PSK

Don't fail wireless interface bringup on empty PSK set. This is a valid
configuration, resulting in a PSK network which can't be connected to.
It does not fail the bringup of the hostapd process.

Keep failing the interface setup in case a password with invalid length
is used.

This is also beneficial when intending to configure a PPSK network. It
allows to create a network where no PPSK is yet set.

Signed-off-by: David Bauer <[email protected]>
(cherry picked from commit 17a71f0c154cebd2e52cd8407531a9a88c931474)

package/network/config/wifi-scripts/files/lib/netifd/hostapd.sh

@@ -697,7 +697,7 @@ hostapd_set_bss_options() {
 				append bss_conf "wpa_psk=$key" "$N"
 			elif [ ${#key} -ge 8 ] && [ ${#key} -le 63 ]; then
 				append bss_conf "wpa_passphrase=$key" "$N"
-			elif [ -n "$key" ] || [ -z "$wpa_psk_file" ]; then
+			elif [ -n "$key" ]; then
 				wireless_setup_vif_failed INVALID_WPA_PSK
 				return 1
 			fi