drivers:misc: ti-st: fix unexpected UART close

If suppose the UIM were to die and hence UART were to close when the
Bluetooth/FM or GPS is turned on, prep the ST for a state where-in if
the UIM comes back up, Bluetooth/FM/GPS can be turned on.
Signed-off-by: Pavan Savoy <pavan_savoy@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/misc/ti-st/st_core.c

@@ -727,6 +727,7 @@ static void st_tty_close(struct tty_struct *tty)
 		if (st_gdata->is_registered[i] == true)
 			pr_err("%d not un-registered", i);
 		st_gdata->list[i] = NULL;
+		st_gdata->is_registered[i] = false;
 	}
 	st_gdata->protos_registered = 0;
 	spin_unlock_irqrestore(&st_gdata->lock, flags);