Unify type of "cpu_idx" across PSCI module.

NOTE for platform integrators:
   API `plat_psci_stat_get_residency()` third argument
   `last_cpu_idx` is changed from "signed int" to the
   "unsigned int" type.

Issue / Trouble points
1. cpu_idx is used as mix of `unsigned int` and `signed int` in code
with typecasting at some places leading to coverity issues.

2. Underlying platform API's return cpu_idx as `unsigned int`
and comparison is performed with platform specific defines
`PLAFORM_xxx` which is not consistent

Misra Rule 10.4:
The value of a complex expression of integer type may only be cast to
a type that is narrower and of the same signedness as the underlying
type of the expression.

Based on above points, cpu_idx is kept as `unsigned int` to match
the API's and low-level functions and platform defines are updated
where ever required

Signed-off-by: Deepika Bhavnani <deepika.bhavnani@arm.com>
Change-Id: Ib26fd16e420c35527204b126b9b91e8babcc3a5c
diff --git a/lib/psci/psci_private.h b/lib/psci/psci_private.h
index 0f25e65..e2dcfa8 100644
--- a/lib/psci/psci_private.h
+++ b/lib/psci/psci_private.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2020, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -301,7 +301,7 @@
 int psci_cpu_on_start(u_register_t target_cpu,
 		      const entry_point_info_t *ep);
 
-void psci_cpu_on_finish(int cpu_idx, const psci_power_state_t *state_info);
+void psci_cpu_on_finish(unsigned int cpu_idx, const psci_power_state_t *state_info);
 
 /* Private exported functions from psci_off.c */
 int psci_do_cpu_off(unsigned int end_pwrlvl);
@@ -312,7 +312,7 @@
 			psci_power_state_t *state_info,
 			unsigned int is_power_down_state);
 
-void psci_cpu_suspend_finish(int cpu_idx, const psci_power_state_t *state_info);
+void psci_cpu_suspend_finish(unsigned int cpu_idx, const psci_power_state_t *state_info);
 
 /* Private exported functions from psci_helpers.S */
 void psci_do_pwrdown_cache_maintenance(unsigned int pwr_level);