powerpc: Fix interrupt range check on debug exception

We do not want to take single step and branch-taken debug exception
in kernel exception code. But the address range check was not covering
all kernel exception handlers address range.

With this patch we defined the interrupt_end label which defines the
end on kernel exception code. So now we check interrupt_base to
interrupt_end range for not handling debug exception in kernel
exception entry.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S
index 7a2e5e4..97e2671 100644
--- a/arch/powerpc/kernel/head_44x.S
+++ b/arch/powerpc/kernel/head_44x.S
@@ -769,6 +769,8 @@
 	 */
 	DEBUG_CRIT_EXCEPTION
 
+interrupt_end:
+
 /*
  * Global functions
  */