omp_lib.f90.in: Deprecate omp_lock_hint_* for OpenMP 5.0

The omp_lock_hint_* parameters were deprecated in favor of
omp_sync_hint_*.  While omp.h contained deprecation markers for those,
the omp_lib module only contained them for omp_{g,s}_nested.

Note: The -Wdeprecated-declarations warning will only become active once
openmp_version / _OPENMP is bumped from 201511 (4.5) to 201811 (5.0).

libgomp/ChangeLog:

	* omp_lib.f90.in: Tag omp_lock_hint_* as being deprecated when
	_OPENMP >= 201811.