drirc: Enable glthread for dolphin/citra/yuzu.

drirc: Enable glthread for dolphin/citra/yuzu.

Dolphin: 75 fps -> 88 fps - Super Mario Galaxy
Citra:   81 fps -> 91 fps - A Link Between Worlds
Yuzu:    21 fps -> 27 fps - Super Mario Odyssey

Dolphin still has many syncs because of glFenceSync and glClientWaitSync.
Moving them to the dispatcher thread might yield another speedup.

Yuzu uses a compatible profile by default. This benchmark used the variable
MESA_GL_VERSION_OVERRIDE=4.5FC to overwrite this behavior.

This profilation was done on a mobile i7-8550U CPU with i965.

Signed-off-by: Markus Wick <markus@selfnet.de>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>