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>

drivers/staging/rts5208/rtsx.c

@@ -414,8 +414,6 @@ static void rtsx_shutdown(struct pci_dev *pci)
 		pci_disable_msi(pci);
 
 	pci_disable_device(pci);
-
-	return;
 }
 
 static int rtsx_control_thread(void *__dev)