Fix the type of pte_pa as when it is passed into _kvm_pa2off it is either
a uint64_t or a pointer to an off_t. With it being a u_long can result in
incorrect values being returned.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@273166 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f