ar71xx: enable the Seama firmware parser

It will be used for the WD My Net N600 board.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38154 3c298f89-4303-0410-b956-a3cf2f4a3e73
ar71xx: image: simplify mynet_n600_mtdlayout

Remove the kernel and rootfs partitions. The Seama
parser can find those automatically:

  0x000000070000-0x000000ff0000 : "firmware"
  2 seama-fw partitions found on MTD device firmware
  0x000000070000-0x0000001b0000 : "kernel"
  0x0000001b0000-0x000000ff0000 : "rootfs"
  mtd: partition "rootfs" set to be root filesystem
  1 squashfs-split partitions found on MTD device rootfs
  0x000000360000-0x000000ff0000 : "rootfs_data"
  0x000000ff0000-0x000001000000 : "radiocfg"

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38155 3c298f89-4303-0410-b956-a3cf2f4a3e73