target/arm: properly document FEAT_CRC32

target/arm: properly document FEAT_CRC32

This is a mandatory feature for Armv8.1 architectures but we don't
state the feature clearly in our emulation list. Also include
FEAT_CRC32 comment in aarch64_max_tcg_initfn for ease of grepping.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20230824075406.1515566-1-alex.bennee@linaro.org
Cc: qemu-stable@nongnu.org
Message-Id: <20230222110104.3996971-1-alex.bennee@linaro.org>
[PMM: pluralize 'instructions' in docs]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>