build/r300: group build target in common subdir

Allows us to share more code between different targets.

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Marek Olšák <marek.olsak@amd.com>
diff --git a/configure.ac b/configure.ac
index 4c99603..b1cb89e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1767,7 +1767,7 @@
             PKG_CHECK_MODULES([RADEON], [libdrm_radeon >= $LIBDRM_RADEON_REQUIRED])
             gallium_require_llvm "Gallium R300"
             GALLIUM_DRIVERS_DIRS="$GALLIUM_DRIVERS_DIRS r300"
-            gallium_check_st "radeon/drm" "dri-r300" "" "" "xvmc-r300" "vdpau-r300"
+            gallium_check_st "radeon/drm" "r300/dri" "" "" "r300/xvmc" "r300/vdpau"
             ;;
         xr600)
             HAVE_GALLIUM_R600=yes
@@ -2032,7 +2032,6 @@
 		src/gallium/targets/dri-i915/Makefile
 		src/gallium/targets/dri-ilo/Makefile
 		src/gallium/targets/dri-nouveau/Makefile
-		src/gallium/targets/dri-r300/Makefile
 		src/gallium/targets/dri-r600/Makefile
 		src/gallium/targets/dri-radeonsi/Makefile
 		src/gallium/targets/dri-swrast/Makefile
@@ -2043,9 +2042,11 @@
 		src/gallium/targets/osmesa/Makefile
 		src/gallium/targets/osmesa/osmesa.pc
 		src/gallium/targets/pipe-loader/Makefile
+		src/gallium/targets/r300/dri/Makefile
+		src/gallium/targets/r300/vdpau/Makefile
+		src/gallium/targets/r300/xvmc/Makefile
 		src/gallium/targets/libgl-xlib/Makefile
 		src/gallium/targets/vdpau-nouveau/Makefile
-		src/gallium/targets/vdpau-r300/Makefile
 		src/gallium/targets/vdpau-r600/Makefile
 		src/gallium/targets/vdpau-radeonsi/Makefile
 		src/gallium/targets/vdpau-softpipe/Makefile
@@ -2056,7 +2057,6 @@
 		src/gallium/targets/xorg-r600/Makefile
 		src/gallium/targets/xorg-radeonsi/Makefile
 		src/gallium/targets/xvmc-nouveau/Makefile
-		src/gallium/targets/xvmc-r300/Makefile
 		src/gallium/targets/xvmc-r600/Makefile
 		src/gallium/targets/xvmc-softpipe/Makefile
 		src/gallium/tests/trivial/Makefile