Blackfin: only enable hardware error irq by default

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/cpu/blackfin/cpu.c b/cpu/blackfin/cpu.c
index 53de5ab..0c79932 100644
--- a/cpu/blackfin/cpu.c
+++ b/cpu/blackfin/cpu.c
@@ -133,9 +133,8 @@
 	bfin_write_EVT15(evt_default);
 	bfin_write_ILAT(0);
 	CSYNC();
-	/* enable all interrupts except for core timer */
-	irq_flags = 0xffffffbf;
+	/* enable hardware error irq */
+	irq_flags = 0x3f;
 	local_irq_enable();
-	CSYNC();
 	return 0;
 }