Staging: sb105x: Remove redundant null check

This patch fixes the following Sparse information in sb_pci_mp.c-

~/git/kernels/linux/drivers/staging/sb105x/sb_pci_mp.c:1813
mp_unregister_driver() info: redundant null check on drv->state calling kfree()
Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/sb105x/sb_pci_mp.c

@@ -1808,10 +1808,7 @@ void mp_unregister_driver(struct uart_driver *drv)
     drv->tty_driver = NULL;
 
 
-    if (drv->state)
-    {
-        kfree(drv->state);
-    }
+    kfree(drv->state);
 
 }