Pass yuvconstants to YUV conversions for neon 64 bit

Pass yuvconstants to YUV conversions for neon 64 bit

SETUP provided by zhongwei.yao@linaro.org

Previously the 64 bit Neon code had hard coded constants in the setup macro
for YUV conversion, while 32 bit Neon code supported the yuvconstants
parameter.

This change accepts the constants passed to the YUV conversion row function,
allowing different color spaces to be respected - naming JPEG and BT.709.
As well as the existing BT.601.

TBR=harryjin@google.com
BUG=libyuv:472
Committed: https://chromium.googlesource.com/libyuv/libyuv/+/013080f2d2153e6c5253573fa86a63e4b5843f71

[fbarchard, 2015-10-06 00:08:16]

fbarchard@chromium.org changed reviewers:
+ harryjin@google.com

[fbarchard, 2015-10-06 00:47:06]

fbarchard@chromium.org changed reviewers:
+ zhongwei.yao@linaro.org

[fbarchard, 2015-10-07 04:46:38]

fbarchard@chromium.org changed reviewers:
+ fbarchard@chromium.org

[fbarchard, 2015-10-07 04:46:38]

nv21 now uses same matrix as nv12.
tested the code compiles on ios aarch64, but havent run unittests.

[fbarchard1, 2015-10-07 05:19:21]

Committed patchset #8 (id:140001) manually as
013080f2d2153e6c5253573fa86a63e4b5843f71 (presubmit successful).

[harryjin, 2015-10-07 05:31:23]

lgtm