target/arm: Correct condition of aa64_atomics feature function

target/arm: Correct condition of aa64_atomics feature function

The ARMv8.1-Atomics feature (renamed FEAT_LSE in more modern versions
of the Arm ARM) has always ben indicated by ID_AA64ISAR0.ATOMIC being
0b0010 or greater; 0b0001 is a reserved unused value.

We were incorrectly checking for != 0; this had no harmful effects
because all the CPUs set their value for this field to either 0
(for not having the feature) or 2 (if they do have it), but it's
better to match what the architecture specifies here.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250819145659.2165160-1-peter.maydell@linaro.org