Hexagon (target/hexagon) make VyV operands use a unique temp

Hexagon (target/hexagon) make VyV operands use a unique temp

VyV operand is only used in the vshuff and vdeal instructions.  These
instructions write to both VyV and VxV operands.  In the case where
both operands are the same register, we need a separate location for
VyV.  We use the existing vtmp field in CPUHexagonState.

Test case added in tests/tcg/hexagon/hvx_misc.c

Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220718230320.24444-2-tsimpson@quicinc.com>