Fix header output when -P is specified and (ncpus - 1) != maxid.

Reported by:	Hiroaki Shimizu
PR:		152738


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271410 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Fix a bug which could break extended attributes in a dump output.
This occurred when a file was >892kB long and had a large data (>1kB)
in the extended attributes.

Reported by:	Masashi Toriumi
Reviewed by:	mckusick


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271411 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f