Move to new override syntax

Signed-off-by: Andreas Müller <schnitzeltony@gmail.com>

recipes-games/doomretro/doomretro.bb

@@ -17,7 +17,7 @@ SRCREV = "2655445b7a82643568bd58192185b25a864e5380"
 PV = "3.5.10"
 S = "${WORKDIR}/git"
 
-do_install_append() {
+do_install:append() {
     install -d ${D}${datadir}/applications
     install ${WORKDIR}/${BPN}.desktop ${D}${datadir}/applications
 

recipes-games/dxx-rebirth/d1x-rebirth_git.bb

@@ -53,4 +53,4 @@ do_install() {
     install ${WORKDIR}/descent.hog ${WORKDIR}/descent.pig ${WORKDIR}/d1xr-sc55-music.dxa ${D}${datadir}/${BPN}
 }
 
-RRECOMMENDS_${PN} = "tremor"
+RRECOMMENDS:${PN} = "tremor"

recipes-games/opentyrian/opentyrian.bb

@@ -45,4 +45,4 @@ do_install() {
     find ${D}${datadir}/games/tyrian -name '*.tfp' -exec rm -f {} \; 
 }
 
-FILES_${PN} += "${datadir}/games"
+FILES:${PN} += "${datadir}/games"