ramips: enable additional GPIOs on HAME MPR-A1

According to the pcb tracing results[1] by anton.rad[2] MPR-A1s expose
6 unused GPIOs, only one of them working as configured in the current
DTS. This patch enables GPIO22-26.

Tested on hardware.

[1] http://i.imgur.com/kHVW2Ox.jpg
[2] https://forum.openwrt.org/viewtopic.php?pid=222698#p222698

Signed-off-by: Paul Fertser <fercerpav@gmail.com>
SVN-Revision: 42178