[HVM][VMX] expose PSE feature to HVM guests if PAE is turned on in

[HVM][VMX] expose PSE feature to HVM guests if PAE is turned on in
config file, with this change, RHEL4 IA32 SMP guest can boot.
But because we don't support 4Mbytes PSE pages, so x86_32 HVM guest
can NOT use PSE feature. However user may have "pae=1" in config file,
which causes PSE feature seen by x86_32 HVM guest, and it will then use
4Mbytes PSE pages. In this case, we will have to crash x86_32 HVM.
So when running x86_32 HVM guest, user need pay attention not to have
"pae=1" in config file.

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