agl_bbe.inc: remove old graphics preferences

agl_bbe.inc: remove old graphics preferences

Latest TI graphics completely redone its dependencies and preferences
to be aligned with upstream and use Mesa packages as proper providers
for GBM, EGL, GLES, etc. components. There's no more need for local
workarounds to adjust graphics settings.

Note: SGX is currently set in meta-ti-bsp to fall back to software
rendering and will be fixed later. Rogue in newer K3 devices is fully
functioning though.

Bug-AGL: SPEC-4723

Change-Id: I072a5e25bdbb444db8e7d4b87a1f181c349240ea
Signed-off-by: Denys Dmytriyenko <denys@konsulko.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/28744
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Reviewed-by: Scott Murray <scott.murray@konsulko.com>
Tested-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>