meta-agl-profile-graphical: backport weston drm tear-down fix

meta-agl-profile-graphical: backport weston drm tear-down fix

As part of the fixes for compositor start up failures on UpSquared,
backport the fix for cleaning up the DRM backend when start up fails.
This does result in start up working on the UpSquared, but usually
after one or more failures, so a systemd dependency to avoid that will
also be added via another change.  However, this particular fix still
seems worth applying as it may be potentially useful for AGL members
that roll their own customized distributions.

Bug-AGL: SPEC-3518

Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: I825e9935706fa09c44cf4a57b33cb910dc0f3aaf
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/25711
Tested-by: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
ci-image-build: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
ci-image-boot-test: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>