target/arm: use raise_exception_ra for MTE check failure

target/arm: use raise_exception_ra for MTE check failure

Now that raise_exception_ra restores the state before raising the
exception we can use restore_exception_ra to perform the state restore +
exception raising without clobbering the syndrome.

Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jamie Iles <jamie@nuviainc.com>
[PMM: Keep the one line of the comment that is still relevant]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>