cns21xx: enable XZ_DEC_ARM and XZ_DEC_BCJ kernel options

cns21xx: enable XZ_DEC_ARM and XZ_DEC_BCJ kernel options

Squashfs is unable to decompress some blocks without that:

  [    0.970000] SQUASHFS error: xz_dec_run error, data probably corrupt
  [    0.980000] SQUASHFS error: squashfs_read_data failed to read block 0x29a72
  [    0.990000] SQUASHFS error: Unable to read fragment cache entry [29a72]
  [    1.000000] SQUASHFS error: Unable to read page, block 29a72, size 14c50
  [    1.010000] SQUASHFS error: Unable to read fragment cache entry [29a72]
  [    1.020000] SQUASHFS error: Unable to read page, block 29a72, size 14c50
  [    1.260000] SQUASHFS error: xz_dec_run error, data probably corrupt

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@37965 3c298f89-4303-0410-b956-a3cf2f4a3e73