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/include/export/lib/utils_def_exp.h b/include/export/lib/utils_def_exp.h
index 86c409c..d4a4a85 100644
--- a/include/export/lib/utils_def_exp.h
+++ b/include/export/lib/utils_def_exp.h
@@ -25,11 +25,13 @@
 # define   L(_x)	(_x)
 # define  LL(_x)	(_x)
 #else
-# define   U(_x)	(_x##U)
+# define  U_(_x)	(_x##U)
+# define   U(_x)	U_(_x)
 # define  UL(_x)	(_x##UL)
 # define ULL(_x)	(_x##ULL)
 # define   L(_x)	(_x##L)
 # define  LL(_x)	(_x##LL)
+
 #endif
 
 #endif /* ARM_TRUSTED_FIRMWARE_EXPORT_LIB_UTILS_DEF_EXP_H */