buildroot

imx-uuc: switch to open source version

The tool will be maintained as an open source project.
The repository can be found at:
https://github.com/NXPmicro/imx-uuc

This patch is based on the Yocto equivalent:
https://github.com/Freescale/meta-freescale/commit/9b56bf13

Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>