mpc85xx: p1020: convert Aerohive AP330/AP350 to simpleImage

mpc85xx: p1020: convert Aerohive AP330/AP350 to simpleImage

with 6.1, the kernel no longer fitted into the 16 MiB and
kicking down the can and increasing KERNEL_SIZE to 20 MiB
didn't help as the device failed to boot.

Using 'kernel-bin | gzip | uimage gzip' didn't work since the
uboot does not have enough heap to decompress these big kernels.

And finally playing around with uboot was more a hassle than
converting this device to take the simpleImage-boot-route in
the future.

Note: The device now takes even longer on the first boot-up after
the flash due to JFFS2 initializing all the remaining flash.
Be prepared to wait up to 10 minutes before the green status LED
stops blinking and will shine a solid green!

(On the plus site: the device now has ~10 MiB of additional
space for rootfs+rootfs_data).

Note2: This patch includes a kernel patch refresh.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>