meson: add common hw files

meson: add common hw files

Those files will be compiled once per base architecture ("arm" in this
case), instead of being compiled for every variant/bitness of
architecture.

We make sure to not include target cpu definitions (exec/cpu-defs.h) by
defining header guard directly. This way, a given compilation unit can
access a specific cpu definition, but not access to compile time defines
associated.

Previous commits took care to clean up some headers to not rely on
cpu-defs.h content.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20250325045915.994760-24-pierrick.bouvier@linaro.org>