jetson-tk1: fix UBOOT_MACHINE
jetson-tk1: fix UBOOT_MACHINE

since jetson-tk1_config does not exist for U-Boot.

Signed-off-by: Luca Nardelli <b752a72e5c9d83dc8f662cb186753cf18fc83995@protonmail.com>

madisongh/meta-tegra,madisongh/meta-tegra,madisongh/meta-tegra,madisongh/meta-tegra,madisongh/meta-tegra