Remove special casing for running in the simulator from the kernel
and instead add platform, firmware and EFI stubs to the loader.
The net effect of this change is that besides a special console and
disk driver, the kernel has no knowledge of the simulator. This has
the following advantages:
o Simulator support is much harder to break,
o It's easier to make use of more feature complete simulators.

This would only need a change in the simulator specific loader,

o Running SMP kernels within the simulator. Note that ski at this

time does not simulate IPIs, so there's no way to start APs.

The platform, firmware and EFI stubs describe the following hardware:
o 4 CPU Itanium,
o 128 MB RAM within the 4GB address space,
o 64 MB RAM above the 4GB address space.

This change introduces an unofficial SSC call SSC_SAL_SET_VECTORS
which is ignored by the simulator.

Tested with: ski (version 0.943 for linux)