macintosh/via-macii: Access autopoll_devs when inside lock

The interrupt handler should be excluded when accessing the autopoll_devs
variable.

Fixes: d95fd5fc ("m68k: Mac II ADB fixes") # v5.0+
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/5952dd8a9bc9de90f1acc4790c51dd42b4c98065.1593318192.git.fthain@telegraphics.com.au

drivers/macintosh/via-macii.c

@@ -270,15 +270,12 @@ static int macii_autopoll(int devs)
 	unsigned long flags;
 	int err = 0;
 
+	local_irq_save(flags);
+
 	/* bit 1 == device 1, and so on. */
 	autopoll_devs = devs & 0xFFFE;
 
-	if (!autopoll_devs)
-		return 0;
-
-	local_irq_save(flags);
-
-	if (current_req == NULL) {
+	if (autopoll_devs && !current_req) {
 		/* Send a Talk Reg 0. The controller will repeatedly transmit
 		 * this as long as it is idle.
 		 */