u-boot: rename u-boot-imx to u-boot-seco-imx
Renamed u-boot-imx recipes to make it reusable for Edgehog builds.
Updated recipes that were dependent on it.
Moved PV back to recipes name.
SRCREV.conf in manifest repo should be updated once this MR is merged.
I`m talking about this:
https://git.seco.com/seco-ne/yocto/manifest/-/blob/kirkstone/SRCREV.conf#L20
I`m not exactly sure how it should be done properly.