Update libyuv version to fix compile errors on old gcc versions

[nanang]

Current bundled libyuv seems to have build issue on older gcc, e.g:

../../yuv/source/row_common.cc: In function ‘void libyuv::YuvPixel(uint8, uint8, uint8, uint8*, uint8*, uint8*, const libyuv::YuvConstants*)’:
../../yuv/source/row_common.cc:1256: error: invalid types ‘const signed char __vector__[int]’ for array subscript
../../yuv/source/row_common.cc:1257: error: invalid types ‘const signed char __vector__[int]’ for array subscript
../../yuv/source/row_common.cc:1258: error: invalid types ‘const signed char __vector__[int]’ for array subscript
../../yuv/source/row_common.cc:1259: error: invalid types ‘const signed char __vector__[int]’ for array subscript
../../yuv/source/row_common.cc:1260: error: invalid types ‘const short int __vector__[int]’ for array subscript

Also in the source code around the compile error location, there is this warning:

// Caveat GCC 4.2 to 4.7 have a known issue using vectors with const.

The issue seem to be fixed already, as described ​here. So let's update our libyuv version.

[nanang]

In 5633:

Re #2004: Update libyuv version from libyuv git master repo dated 27 July 2017, the compile errors on old gcc versions issue persists though.

[nanang]

It seems that this issue was fixed at some point but for some reason it was reverted back. So the changeset r5633 in this ticket just updates the libyuv version.