staging: rts5208: Remove unncessary return in function returning void

This patch fixes checkpatch.pl warning in rtsx.c file.
WARNING: void function return statements are not generally useful

Signed-off-by: Tapasweni Pathak <tapaswenipathak@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>