staging: rts5139: fix pointer coding style

This will remove the following checkpatch.pl error:
ERROR: "foo * bar" should be "foo *bar"

Signed-off-by: Márton Németh <nm127@freemail.hu>
Acked-by: edwin_rong <edwin_rong@realsil.com.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>