Forward some UVM from matt-nb5-mips64.  Add UVM_KMF_COLORMATCH flag.
When uvm_map gets passed UVM_FLAG_COLORMATCH, the align argument contains
the color of the starting address to be allocated (0..colormask).
When uvm_km_alloc is passed UVM_KMF_COLORMATCH (which can only be used with
UVM_KMF_VAONLY), the align argument contain the color of the starting address
to be allocated.
Change uvm_pagermapin to use this.  When mapping user pages in the kernel,
if colormatch is used with the color of the starting user page then the kernel
mapping will be congruent with the existing user mappings.

(matt)