fconf: Fix misra issues

MISRA C-2012 Rule 20.7:
Macro parameter expands into an expression without being wrapped by parentheses.

MISRA C-2012 Rule 12.1:
Missing explicit parentheses on sub-expression.

MISRA C-2012 Rule 18.4:
Essential type of the left hand operand is not the same as that of the right
operand.

Include does not provide any needed symbols.

Change-Id: Ie1c6451cfbc8f519146c28b2cf15c50b1f36adc8
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>
diff --git a/include/lib/object_pool.h b/include/lib/object_pool.h
index 0f85331..66e8c47 100644
--- a/include/lib/object_pool.h
+++ b/include/lib/object_pool.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2020, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -56,13 +56,13 @@
  */
 static inline void *pool_alloc_n(struct object_pool *pool, size_t count)
 {
-	if (pool->used + count > pool->capacity) {
+	if ((pool->used + count) > pool->capacity) {
 		ERROR("Cannot allocate %zu objects out of pool (%zu objects left).\n",
 		      count, pool->capacity - pool->used);
 		panic();
 	}
 
-	void *obj = (char *)(pool->objects) + pool->obj_size * pool->used;
+	void *obj = (char *)(pool->objects) + (pool->obj_size * pool->used);
 	pool->used += count;
 	return obj;
 }