exec: Rename 'exec/user/guest-base.h' as 'user/guest-base.h'

The include/user/ directory contains the user-emulation
specific headers. Move guest-base.h there too.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Anton Johansson <anjo@rev.ng>
Message-Id: <20240418192525.97451-15-philmd@linaro.org>
3 files changed