staging: vt6655: return at the ond of case body

This patch will unify exit point for s_uGetDataDuration function.

Signed-off-by: Matej Dujava <mdujava@kocurkovo.cz>
Link: https://lore.kernel.org/r/1588512552-12297-5-git-send-email-mdujava@kocurkovo.cz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>