microblaze: intc: Refactor DT sanity check

Avoid funky casts and arithmetic.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/microblaze/kernel/intc.c b/arch/microblaze/kernel/intc.c
index 01ae730..8965fd3 100644
--- a/arch/microblaze/kernel/intc.c
+++ b/arch/microblaze/kernel/intc.c
@@ -157,7 +157,7 @@
 		return ret;
 	}
 
-	if (intr_mask > (u32)((1ULL << nr_irq) - 1))
+	if (intr_mask >> nr_irq)
 		pr_info(" ERROR: Mismatch in kind-of-intr param\n");
 
 	pr_info("%s: num_irq=%d, edge=0x%x\n",