Revision 355790

vfs: flatten vop vectors

This eliminates the following loop from all VOP calls:

while(vop != NULL && \
    vop->vop_spare2 == NULL && vop->vop_bypass == NULL)
        vop = vop->vop_default;

Reviewed by:	jeff
Tesetd by:	pho
Differential Revision:	https://reviews.freebsd.org/D22738