Revert "Work around rcar-gen3 gstreamer issues"

Revert "Work around rcar-gen3 gstreamer issues"

This reverts commit a7bb29c2984f993a2a5226ffe8d510e4ca53b0f1.
meta-renesas' kirkstone-dev branch now has a complete set of
gstreamer 1.20.3 recipes as was done for scarthgap, so these
changes are no longer required.

Bug-AGL: SPEC-5393

Change-Id: Ib1c61e81e9cd65f2a627dc7724e719037ebf4d73
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/30893
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Tested-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>