conf/layer.conf: Remove meta-lts-mixins

Remove layer dependency from meta-lts-mixins 'scarthgap/u-boot'
because now the BSP supports styhead which brings U-Boot 2024.07.

Signed-off-by: Leon Anavi <leon.anavi@konsulko.com>

conf/layer.conf

@@ -11,9 +11,6 @@ BBFILE_PRIORITY_raspberrypi = "9"
 
 LAYERSERIES_COMPAT_raspberrypi = "styhead"
 LAYERDEPENDS_raspberrypi = "core"
-# Recommended for u-boot support for raspberrypi5
-# https://git.yoctoproject.org/meta-lts-mixins 'scarthgap/u-boot' branch
-LAYERRECOMMENDS_raspberrypi = "lts-u-boot-mixin"
 
 # Additional license directories.
 LICENSE_PATH += "${LAYERDIR}/files/custom-licenses"