add missing files for make dist

when creating the package tarball, autogen.sh is handy to have and
the header files are necessary for compilation.

TEST="make dist should include autogen.sh, loadsurface.h and"
TEST="loadsurface_yuv.h on the final tarballs."
TEST="Then tarball user can compile in the same way as github clone"

Signed-off-by: Daniel Charles <daniel.charles@intel.com>

Makefile.am

@@ -43,3 +43,7 @@ MAINTAINERCLEANFILES = \
 	aclocal.m4 compile config.guess config.sub \
 	configure depcomp install-sh ltmain.sh     \
 	Makefile.in missing
+
+EXTRA_DIST = \
+        autogen.sh \
+        $(NULL)

common/Makefile.am

@@ -58,3 +58,8 @@ libva_display_la_LIBADD	= $(libva_display_libs)
 
 # Extra clean files so that maintainer-clean removes *everything*
 MAINTAINERCLEANFILES = Makefile.in
+
+EXTRA_DIST = \
+	loadsurface.h		\
+	loadsurface_yuv.h	\
+	$(NULL)