omap: Add support for kernel 4.9

omap: Add support for kernel 4.9

This adds support for kernel 4.9 and replaces the kernel 4.4 support.

These are lynxis test results:
panda-board a3 - works, but no network, but master/4.4 doesn't have network either.
panda-board-a4 - u-boot SPL refuse to boot.
beaglebone-black - works
beagle-board - usb attached network doesn't come up and I doesn't have a serial around.
beagle-board-xm - ToDo: image code is missing.

Kernel 4.4 does not look better, so we merge this anyway.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Alexander Couzens <lynxis@fe80.eu>