add syscall emulation page table fault so we can allocate more stack pages

add syscall emulation page table fault so we can allocate more stack pages

src/cpu/simple/base.cc:
    add syscall emulation page table fault so we can allocate more stack pages
    FaultBase::invoke will do this, we don't need to do it here
src/sim/faults.hh:
    I have no idea why this #if was there... gone
src/sim/process.cc:
    make stack_min actually be the current minimum

--HG--
extra : convert_revision : 9786b39f2747b94654a5d77c74243cd20503add4