VMX: VMFUNC and #VE definitions and detection

VMX: VMFUNC and #VE definitions and detection

Currently, neither is enabled globally but may be enabled on a per-VCPU
basis by the altp2m code.

Remove the check for EPTE bit 63 == zero in ept_split_super_page(), as
that bit is now hardware-defined.

Signed-off-by: Ed White <edmund.h.white@intel.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Jun Nakajima <jun.nakajima@intel.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>