Blackfin arch: Fix bug - HW Errors never recover on BF548

The kernel does not properly clear the EBIU Error Master (EBIU_ERRMST) Register
on BF548, which causes the kernel to panic.

We need to make sure that we clear the EBIU_ERRMST (necessary on BF54x)

Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

diff --git a/arch/blackfin/mach-common/interrupt.S b/arch/blackfin/mach-common/interrupt.S
index 647f0f5..4a2ec7a 100644
--- a/arch/blackfin/mach-common/interrupt.S
+++ b/arch/blackfin/mach-common/interrupt.S
@@ -179,7 +179,16 @@
 	call _trap_c;
 	SP += 12;
 
+#ifdef EBIU_ERRMST
+	/* make sure EBIU_ERRMST is clear */
+	p0.l = LO(EBIU_ERRMST);
+	p0.h = HI(EBIU_ERRMST);
+	r0.l = (CORE_ERROR | CORE_MERROR);
+	w[p0] = r0.l;
+#endif
+
 	call _ret_from_exception;
+
 .Lcommon_restore_all_sys:
 	RESTORE_ALL_SYS
 	rti;