Wrong log domain for lots of plugins

[Kekun]

Most plugins don't use the correct log domain, they use GamesDesktop instead of their own:

$ git grep "G_LOG_DOMAIN"
plugins/amiga/src/Makefile.am:  -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/atari-2600/src/Makefile.am:     -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/atari-7800/src/Makefile.am:     -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/desktop/src/Makefile.am:        -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/doom/src/Makefile.am:   -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/dreamcast/src/Makefile.am:      -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/game-boy-advance/src/Makefile.am:       -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/game-boy/src/Makefile.am:       -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/game-cube/src/Makefile.am:      -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/love/src/Makefile.am:   -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/mame/src/Makefile.am:   -DG_LOG_DOMAIN=\"GamesMame\" \
plugins/master-system/src/Makefile.am:  -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/mega-drive/src/Makefile.am:     -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/neo-geo-pocket/src/Makefile.am: -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/nes/src/Makefile.am:    -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/nintendo-64/src/Makefile.am:    -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/nintendo-ds/src/Makefile.am:    -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/pc-engine/src/Makefile.am:      -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/sega-saturn/src/Makefile.am:    -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/snes/src/Makefile.am:   -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/steam/src/Makefile.am:  -DG_LOG_DOMAIN=\"GamesSteam\" \
plugins/wii-ware/src/Makefile.am:       -DG_LOG_DOMAIN=\"GamesDesktop\" \
plugins/wii/src/Makefile.am:    -DG_LOG_DOMAIN=\"GamesDesktop\" \