ath79: fix TPLINK_HWREV field for TL-WR1043ND v4
Required to allow sysupgrades from OpenWrt 19.07.
Closes #7071
Fixes: 98fbf2edc021 ("ath79: move TPLINK_HWID/_HWREV to parent for tplink-safeloader")
Tested-by: J. Burfeind <[email protected]>
Signed-off-by: Matthias Schiffer <[email protected]>