NEON optimised yuv to rgb conversion

- along the lines of the SSE chroma upsampling.
Total speedup is ~30%.

4% speed loss on YuvToRgbXX conversion using tables instead
of 14-bit fixed precision. TODO(later): investigate, and compare
to x86.

see http://code.google.com/p/webp/issues/detail?id=134

Change-Id: Idc2261037cd13b4553ca20ecc4c4007099c37009

Android.mk

@@ -62,6 +62,7 @@ ifeq ($(TARGET_ARCH_ABI),armeabi-v7a)
   # instructions to be generated for armv7a code. Instead target the neon code
   # specifically.
   LOCAL_SRC_FILES += src/dsp/dec_neon.c.neon
+  LOCAL_SRC_FILES += src/dsp/upsampling_neon.c.neon
   LOCAL_SRC_FILES += src/dsp/enc_neon.c.neon
 endif
 LOCAL_STATIC_LIBRARIES := cpufeatures