fix(rmm): fix MISRA C Rule 12.2 violation

This patch redefines U(_x) macro as (unsigned int)(_x).

Change-Id: Ica96643d646004528314afe5b4d1532466d716c9
Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
diff --git a/lib/common/include/utils_def.h b/lib/common/include/utils_def.h
index 5569675..f028482 100644
--- a/lib/common/include/utils_def.h
+++ b/lib/common/include/utils_def.h
@@ -27,8 +27,7 @@
 # define   L(_x)	(_x)
 # define  LL(_x)	(_x)
 #else
-# define  U_(_x)	(_x##U)
-# define   U(_x)	U_(_x)
+# define   U(_x)	(unsigned int)(_x)
 # define  UL(_x)	(_x##UL)
 # define ULL(_x)	(_x##ULL)
 # define   L(_x)	(_x##L)