Add a new fo_fill_kinfo fileops method

to add type-specific information to struct kinfo_file. - Move the
various fill_*_info() methods out of kern_descrip.c and into the various
file type implementations. - Rework the support for kinfo_ofile to
generate a suitable kinfo_file object for each file and then convert
that to a kinfo_ofile structure rather than keeping a second, different
set of code that directly manipulates type-specific file information. -
Remove the shm_path() and ksem_info() layering violations.

Differential Revision:	https://reviews.freebsd.org/D775
Reviewed by:	kib, glebius (earlier version)

newlib/libc/sys/rtems/include/sys/mman.h

@@ -234,7 +234,6 @@ int	shm_mmap(struct shmfd *shmfd, vm_size_t objsize, vm_ooffset_t foff,
 	    vm_object_t *obj);
 int	shm_map(struct file *fp, size_t size, off_t offset, void **memp);
 int	shm_unmap(struct file *fp, void *mem, size_t size);
-void	shm_path(struct shmfd *shmfd, char *path, size_t size);
 
 #else /* !_KERNEL */