Don't overflow when calculating vm_kmem_size.  This fixes kmem_map too small panics on PAE machines which have odd > 4GB sizes (4.5 gig would render a 20MB of KVA for kmem_map instead of 200MB).
Don't overflow when calculating vm_kmem_size.  This fixes kmem_map
too small panics on PAE machines which have odd > 4GB sizes (4.5 gig
would render a 20MB of KVA for kmem_map instead of 200MB).

Submitted by:	John Cagle <john.cagle@hp.com>, jeff
Reviewed by:	jeff, peter, scottl, lots of USENIX folks

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase