Makefile: Fix generation of flash.bin u-boot.itb with binman

In case binman is enabled, the u-boot.itb is generated using this tool
and there is no direct u-boot.itb target, but instead the binman tool
must be invoked. Add support for this case.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
1 file changed