MIPS: dts/ingenic: Cleanup qi_lb60.dts

Cleanup a bit the Device Tree file:

1. Respect the number of cells in GPIO descriptors and keyboard matrix;
2. Use 'ecc-engine' instead of deprecated 'ingenic,bch-controller'
   property;
3. The NAND's rb-gpios is actually active high;
3. The FRE/FWE pins must be configured in the proper mode for the NAND
   to work if it was not already done by the bootloader.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>