ACPI / resources: free memory on error in add_region_before()

There is a small memory leak on error.

Fixes: 0f1b414d1907 (ACPI / PNP: Avoid conflicting resource reservations)
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/resource.c

@@ -660,8 +660,10 @@ static int add_region_before(u64 start, u64 end, u8 space_id,
 		return -ENOMEM;
 
 	error = request_range(start, end, space_id, flags, desc);
-	if (error)
+	if (error) {
+		kfree(reg);
 		return error;
+	}
 
 	reg->start = start;
 	reg->end = end;