Some kernel versions (and corresponding u-boot) may still need to set uImage,
as preferred image type, since the machine config changes preference to zImage
for newer kernels - keep that for ti33x and omap-a15 stuck on 3.2 and 3.8.
Signed-off-by: Denys Dmytriyenko <denys@ti.com>
Acked-by: Franklin Cooper Jr. <fcooper@ti.com>