Hegerogeneous code needs access to the FOO_CPU_TYPE_NAME()
macro to resolve target CPU types. Move the declaration
(along with the required FOO_CPU_TYPE_SUFFIX) to "cpu-qom.h".

"target/foo/cpu-qom.h" is supposed to be target agnostic
(include-able by any target). Add such mention in the
header.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20231013140116.255-7-philmd@linaro.org>