boards/freescale/common: Introduce genimage.cfg.template_no_boot_part_spl

boards/freescale/common: Introduce genimage.cfg.template_no_boot_part_spl

Modern U-Boot assumes a layout where the first partition is an ext2 and
the kernel and dtb can be found in /boot. In other words, a layout
without boot partition.

Add a genimage.cfg template for the freescale defconfigs with such a
layout.

For now, only the layout with SPL+u-boot.img is added. It's unlikely that
the u-boot.imx approach will be used.

Signed-off-by: Joris Offouga <offougajoris@gmail.com>
Signed-off-by: Pierre-Jean Texier <pjtexier@koncepto.io>
Tested-by: Pierre-Jean Texier <pjtexier@koncepto.io>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>