Presence of any VM_PROT bits in the permission argument on x86 implies
that the entry is readable and valid.

Reported by:	markj
Submitted by:	alc
Tested by:	pho (previous version), markj
MFC after:	3 days


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271716 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Revert unrelated changes accidentally committed in r271192.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271717 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Correct a comment


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271718 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f