Build warnings in linux from quant.cpp

[Pradeep Ramachandran]

The following warnings show up in linux when building the default branch

/home/mcw/Linux_smoketest/x265repo/source/common/quant.cpp: In member function ‘uint32_t x265_12bit::Quant::rdoQuant(const x265_12bit::CUData&, int16_t*, x265_12bit::TextType, uint32_t, bool) [with unsigned int log2TrSize = 4u]’: /home/mcw/Linux_smoketest/x265repo/source/common/quant.cpp:189: instantiated from here /home/mcw/Linux_smoketest/x265repo/source/common/quant.cpp:672: warning: right shift count is negative /home/mcw/Linux_smoketest/x265repo/source/common/quant.cpp:779: warning: right shift count is negative /home/mcw/Linux_smoketest/x265repo/source/common/quant.cpp:857: warning: right shift count is negative /home/mcw/Linux_smoketest/x265repo/source/common/quant.cpp:940: warning: right shift count is negative /home/mcw/Linux_smoketest/x265repo/source/common/quant.cpp:968: warning: right shift count is negative /home/mcw/Linux_smoketest/x265repo/source/common/quant.cpp:971: warning: right shift count is negative

[Deepthi Nandakumar]

Duplicate of #191.