Fix missed override syntax conversions

Fix missed override syntax conversions

The aglrelease/agldevelopment overrides used in poky-agl.conf got
missed during the conversion, update them with the new syntax.

Bug-AGL: SPEC-4052

Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: Ib13491d5834ab68d8b37eddce3d04b77c46968bc
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/26573
Tested-by: Jenkins Job builder account
ci-image-build: Jenkins Job builder account
ci-image-boot-test: Jenkins Job builder account
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>