procstat_getfiles_sysctl: do not require non-null ki_fd

ki_fd is legitimately NULL when 32bit process requests process data
from 64bit host kernel.  The field is not used by the code for sysctl
case;  procstat_getfiles_kvm() checks ki_fd.

PR:	260174
Reported by:	Damjan Jovanovic <damjan.jov@gmail.com>
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week

lib/libprocstat/libprocstat.c

@@ -865,8 +865,6 @@ procstat_getfiles_sysctl(struct procstat *procstat, struct kinfo_proc *kp,
 	cap_rights_t cap_rights;
 
 	assert(kp);
-	if (kp->ki_fd == NULL)
-		return (NULL);
 	switch (procstat->type) {
 	case PROCSTAT_SYSCTL:
 		files = kinfo_getfile(kp->ki_pid, &cnt);