Fix the simulator build.

Fixes the sim build broken by commit 58d3bd08107f44cba79938dd8430e69c0fda4202.

Change-Id: I5a63623363d558783dc5254fdd322080cc2f3525
diff --git a/media/libmedia/fixedfft.cpp b/media/libmedia/fixedfft.cpp
index 28eb05a..9cf05ba 100644
--- a/media/libmedia/fixedfft.cpp
+++ b/media/libmedia/fixedfft.cpp
@@ -26,7 +26,9 @@
 
 #include <stdio.h>
 #include <stdint.h>
+#ifdef __ARM_ARCH__
 #include <machine/cpu-features.h>
+#endif
 
 #define LOG_FFT_SIZE 10
 #define MAX_FFT_SIZE (1 << LOG_FFT_SIZE)