powerpc/watchdog: Don't enable interrupt on PPC64 BookE

Critical interrupts are not handled on PPC64 BookE machines,
so when the first watchdog interrupt fires the machine will
freeze without a warning until it's rebooted by the second
watchdog trigger.
Plus, the interrupt isn't used anyway since the driver
expects a usermode app to ping the watchdog periodically.

Signed-off-by: Laurentiu Tudor <[e-mail]>
Signed-off-by: Scott Wood <[e-mail]>

drivers/watchdog/booke_wdt.c

···
 	val &= ~WDTP_MASK;
 	val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period));
 
+#ifdef CONFIG_PPC_BOOK3E_64
+	/*
+	 * Crit ints are currently broken on PPC64 Book-E, so
+	 * just disable them for now.
+	 */
+	val &= ~TCR_WIE;
+#endif
+
 	mtspr(SPRN_TCR, val);
 }