time: Add padding for the timespec if required

time: Add padding for the timespec if required

If we are running on a 32-bit system with a 64-bit time_t we need to
ensure there is padding around the tv_nsec variable. This is requried as
the timespec is #defined to the __timespec64 struct.

	* time/bits/types/struct_timespec.h: Add padding for the timespec if
	required.