cpu: Move cpu_exec_* to tcg_ops

cpu: Move cpu_exec_* to tcg_ops

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
[claudio: wrapped target code in CONFIG_TCG]
Signed-off-by: Claudio Fontana <cfontana@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210204163931.7358-6-cfontana@suse.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>