audioflinger: Enable ARMv5TE optimized resampler

Previously, the optimized asm option is only enabled when
__ARM_ARCH_5E__ is defined, which is assigned in armv5te.mk
rather than armv7-a series targets.  This patch checks the ARM CPU
feature about half-word multiply instructions to enable ARMv5TE
resampler optimization routines properly.

Change-Id: I4c5a5d8c932416f23bedb0b389db958349f21ea4
diff --git a/services/audioflinger/AudioResampler.cpp b/services/audioflinger/AudioResampler.cpp
index 5dabacb..245bfdf 100644
--- a/services/audioflinger/AudioResampler.cpp
+++ b/services/audioflinger/AudioResampler.cpp
@@ -26,11 +26,15 @@
 #include "AudioResamplerSinc.h"
 #include "AudioResamplerCubic.h"
 
+#ifdef __arm__
+#include <machine/cpu-features.h>
+#endif
+
 namespace android {
 
-#ifdef __ARM_ARCH_5E__  // optimized asm option
+#ifdef __ARM_HAVE_HALFWORD_MULTIPLY // optimized asm option
     #define ASM_ARM_RESAMP1 // enable asm optimisation for ResamplerOrder1
-#endif // __ARM_ARCH_5E__
+#endif // __ARM_HAVE_HALFWORD_MULTIPLY
 // ----------------------------------------------------------------------------
 
 class AudioResamplerOrder1 : public AudioResampler {