automake: handle gallium SUBDIRs in gallium/Makefile

Considering the way we've been consolidating things it makes
sense to add the final two (aux and tests) in here.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
diff --git a/src/Makefile.am b/src/Makefile.am
index 7da91a2..3e736d0 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -48,15 +48,7 @@
 endif
 
 if HAVE_GALLIUM
-SUBDIRS +=			\
-	gallium/auxiliary	\
-	gallium
-
-if HAVE_GALLIUM_TESTS
-SUBDIRS +=			\
-	gallium/tests/trivial	\
-	gallium/tests/unit
-endif
+SUBDIRS += gallium
 endif
 
 EXTRA_DIST = getopt