Clean up p2m functions.

Clean up p2m functions.
1) set_p2m_entry/alloc_p2m_table call domain_crash instead of
domain_crash_synchronous when map_p2m_entry return with failure, or dom0
will crash.
2) free_p2m_table now uses domain as parameter instead of vcpu.
3) add AP p2m initialization logic for VMX domain.
And some coding style cleanups.

Signed-off-by: Xin Li <xin.b.li@intel.com>