lib/extensions/ras: fix bug of binary search

In ras_interrupt_handler(), binary search end was set to the size of
the ras_interrupt_mappings array, which would cause out of bound
access when the input intr_raw is larger than all the elements in
ras_interrupt_mappings.
Signed-off-by: Heyi Guo <guoheyi@linux.alibaba.com>
Change-Id: Id2cff73177134b09d4d8beb596c3429b98ec5066

lib/extensions/ras/ras_common.c

 /*
- * Copyright (c) 2018-2019, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2021, ARM Limited and Contributors. All rights reserved.
  * Copyright (c) 2020, NVIDIA Corporation. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
@@ -139,7 +139,7 @@ static int ras_interrupt_handler(uint32_t intr_raw, uint32_t flags,
 	assert(ras_interrupt_mappings.num_intrs > 0UL);
 
 	start = 0;
-	end = (int) ras_interrupt_mappings.num_intrs;
+	end = (int)ras_interrupt_mappings.num_intrs - 1;
 	while (start <= end) {
 		mid = ((end + start) / 2);
 		if (intr_raw == ras_inrs[mid].intr_number) {