Extending pmap_kenter_pa and pmap_enter.

[Matt Thomas <matt%3am-software.com@localhost>]

I'd like to two add one more argument to pmap_kenter_pa
and two more to pmap_enter.

To pmap_kenter_pa, I want to add a vsize_t after the pa argument:

void pmap_kenter_pa(vaddr_t va, paddr_t pa, vsize_t len, 
    vm_prot_t prot, u_int flags);

To pmap_enter, I want to add the same vsize_t afer the pa argument
but also a struct vm_page * after the vsize_t.

int pmap_enter(pmap_t pmap, vaddr_t va, paddr_t pa, vsize_t len,
    struct vm_page *pg, vm_prot_t prot, u_int flags);

These charge are to take advantage of larger page table entries on
those platforms that have them.  Since pmap_enter implementations
almost always do a PHYS_TO_VM_PAGE, and since the caller usually
has it available, it might as well supply.  If this is to be an
unmanaged mapping (device page), then NULL will be passed for pg.