Update tegra to use binman for image creation. This still includes the
current Makefile logic, but a later patch will remove this. Three output
files are created, all of which combine
SPL and U-Boot:

u-boot-tegra.bin - standard image
u-boot-dtb-tegra.bin - same as u-boot-tegra.bin
u-boot-nodtb-target.bin - includes U-Boot without the appended device tree

The latter is useful for build systems where the device is appended later,
perhaps after being modified.

Signed-off-by: Simon Glass