Fix the build for NEON in libpixelflinger

ARCH_ARM_HAVE_NEON is only ever defined to true, so test for that.
For the NEON function to be used, the file has to include
machine/cpu-features.h so that __ARM_HAVE_NEON is defined.

Change-Id: I0db196b39c493092415859e009531fcff6fc1e8b
Signed-off-by: Kévin PETIT <kevin.petit@arm.com>
diff --git a/libpixelflinger/scanline.cpp b/libpixelflinger/scanline.cpp
index cb2b811..f84a28a 100644
--- a/libpixelflinger/scanline.cpp
+++ b/libpixelflinger/scanline.cpp
@@ -26,6 +26,10 @@
 #include <cutils/memory.h>
 #include <cutils/log.h>
 
+#ifdef __arm__
+#include <machine/cpu-features.h>
+#endif
+
 #include "buffer.h"
 #include "scanline.h"