graphics/mesa: Update to 21.3.4

This is the last mesa release with DRI drivers, next one will only have
the gallium drivers.

Release notes for 21.2.0: https://lists.freedesktop.org/archives/mesa-dev/2021-August/225459.html
Release notes for 21.2.1: https://lists.freedesktop.org/archives/mesa-dev/2021-September/225480.html
Release notes for 21.2.2: https://lists.freedesktop.org/archives/mesa-dev/2021-September/225490.html
Release notes for 21.2.3: https://lists.freedesktop.org/archives/mesa-dev/2021-September/225495.html
Release notes for 21.2.4: https://lists.freedesktop.org/archives/mesa-dev/2021-October/225532.html
Release notes for 21.2.5: https://lists.freedesktop.org/archives/mesa-dev/2021-October/225555.html
Release notes for 21.2.6: https://lists.freedesktop.org/archives/mesa-dev/2021-November/225580.html
Release notes for 21.3.0: https://lists.freedesktop.org/archives/mesa-dev/2021-November/225574.html
Release notes for 21.3.1: https://lists.freedesktop.org/archives/mesa-dev/2021-December/225581.html
Release notes for 21.3.2: https://lists.freedesktop.org/archives/mesa-dev/2021-December/225603.html
Release notes for 21.3.3: https://lists.freedesktop.org/archives/mesa-dev/2021-December/225612.html
Release notes for 21.3.4: https://lists.freedesktop.org/archives/mesa-dev/2022-January/225635.html

MFH: 2022Q1
Reviewed by: zeising (privately)
Sponsored by: Beckhoff Automation GmbH & Co. KG
Differential Revision: https://reviews.freebsd.org/D33332