inspector, c: change expression convert for eq_event_func_call

Previous way of convert:
original: f()
converted: eq_event_func_call(), f()

New way of converted:
original: f()
converted: (eq_event_func_call(), f())

This change is for avoiding a problem of "void value not ignored as it
ought to be".

Signed-off-by: Hitoshi Mitake <mitake.hitoshi@lab.ntt.co.jp>