target/arm: Fix unaligned checks for mte_check1, mte_probe1

target/arm: Fix unaligned checks for mte_check1, mte_probe1

We were incorrectly assuming that only the first byte of an MTE access
is checked against the tags.  But per the ARM, unaligned accesses are
pre-decomposed into single-byte accesses.  So by the time we reach the
actual MTE check in the ARM pseudocode, all accesses are aligned.

We cannot tell a priori whether or not a given scalar access is aligned,
therefore we must at least check.  Use mte_probe_int, which is already
set up for checking multiple granules.

Buglink: https://bugs.launchpad.net/bugs/1921948
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210416183106.1516563-4-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>