board: sl28: generate FIT update image

Generate a FIT update image during build. The image will be called
"u-boot.update" and can be used to build an EFI UpdateCapsule or during
DFU mode. Although, the latter isn't supported because there is no USB
OTG driver yet.

Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
1 file changed