genio: don't force INSTALL_HEADERS=yes for collabora branch

- while it is nice having them, and also a good test of being able to
  build the headers "board-side",  enabling it by default should be a
  global change, and not specific to genio

config/sources/families/genio.conf

@@ -20,7 +20,6 @@ case $BRANCH in
 		declare -g KERNELSOURCE='https://gitlab.collabora.com/mediatek/aiot/linux.git'
 		declare -g KERNELBRANCH='branch:mediatek-next'
 		declare -g EXTRAWIFI="no"
-		declare -g INSTALL_HEADERS="yes"
 		;;
 
 	vendor)