target/arm: Mark LDS{MIN,MAX} as signed operations

target/arm: Mark LDS{MIN,MAX} as signed operations

The operands to tcg_gen_atomic_fetch_s{min,max}_i64 must
be signed, so that the inputs are properly extended.
Zero extend the result afterward, as needed.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/364
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20210602020720.47679-1-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>