Hexagon (target/hexagon) TCG for instructions with multiple definitions

Helpers won't work if there are multiple definitions, so we override these
instructions using #define fGEN_TCG_<tag>.

Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
Message-Id: <1612763186-18161-28-git-send-email-tsimpson@quicinc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>