llvmpipe: lp_test_arit test failed on mips64el and x86-64(if not using sse instruction set)

88/99 mesa:llvmpipe / lp_test_arit FAIL 0.27 s (exit status 1)

/home/suijingfeng/WorkSpace/mesa-20.2.6/build/src/gallium/drivers/llvmpipe/lp_test_arit

round.v1(-0.5): ref = -0, out = -1, precision = -inf bits, FAIL round.v1(0.5): ref = 0, out = 1, precision = -inf bits, FAIL round.v4(-0.5): ref = -0, out = -1, precision = -inf bits, FAIL round.v4(0.5): ref = 0, out = 1, precision = -inf bits, FAIL round.v8(-0.5): ref = -0, out = -1, precision = -inf bits, FAIL round.v8(0.5): ref = 0, out = 1, precision = -inf bits, FAIL

similar with #3264