[guest] Allow more flexible memory configuration

We can now map memory at different addresses, and with different cache
policies, all from the command line. This allows us to more easily
configure a guest for device pass-through.

MAC-180

Test: Ran vmm_unittests.
Change-Id: I52ca3ebab9ceb72a67a23135a1c7cc50ebf19e75
8 files changed