staging: rtl8188eu: cleanup comment in hal8188e_rate_adaptive.c

Cleanup comment in hal8188e_rate_adaptive.c.
Clears checkpatch warnings.

WARNING: Block comments use * on subsequent lines
WARNING: Block comments use a trailing */ on a separate line

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>