include: posix: remove an unreachable clockid_t definition

The clockid_t definition in question is not reachable anymore
because at least one of _CLOCKID_T_DECLARED and __clockid_t_defined
macros is already defined by that point, always making the check fail.

Signed-off-by: Ilya Tagunov <[email protected]>

Author: tagunil

include/zephyr/posix/posix_types.h

@@ -84,11 +84,6 @@ typedef unsigned long useconds_t;
 #endif
 
 /* time related attributes */
-#if !defined(CONFIG_NEWLIB_LIBC) && !defined(CONFIG_ARCMWDT_LIBC)
-#if !defined(__clockid_t_defined) && !defined(_CLOCKID_T_DECLARED)
-typedef uint32_t clockid_t;
-#endif
-#endif /* !CONFIG_NEWLIB_LIBC && !CONFIG_ARCMWDT_LIBC */
 #if !defined(__timer_t_defined) && !defined(_TIMER_T_DECLARED)
 typedef unsigned long timer_t;
 #endif