[media] tm6000: fix OOPS at tm6000_ir_int_stop() and tm6000_ir_int_start()

[ 3755.608233] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[ 3755.616360] IP: [<ffffffffa03b80b7>] tm6000_ir_int_stop+0x10/0x1b [tm6000]
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/tm6000/tm6000-input.c

@@ -377,6 +377,9 @@ int tm6000_ir_int_start(struct tm6000_core *dev)
 {
 	struct tm6000_IR *ir = dev->ir;
 
+	if (!ir)
+		return;
+
 	return __tm6000_ir_int_start(ir->rc);
 }
 
@@ -384,6 +387,9 @@ void tm6000_ir_int_stop(struct tm6000_core *dev)
 {
 	struct tm6000_IR *ir = dev->ir;
 
+	if (!ir || !ir->rc)
+		return;
+
 	__tm6000_ir_int_stop(ir->rc);
 }