QONG: fix and update board config file

Fix flash memory map and other updates for QONG board:

- adjust/fix "kernel_addr" settings
- adjust/fix mtdparts NOR flash settings
- add mtdparts NAND flash mapping
- sort command list
- enable "setexpr" command
- enable ext2 support
- delete bogus comment

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Stefano Babic <sbabic@denx.de>