The -O option for the tplink-v1-header was missing for the TP-Link
TL-WR902AC v1, while safeloader and MTDPARTS where set up with a
single firmware partition.
This led to bootloops after using sysupgrade.
Fixes: FS#3118
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>