KVM: nVMX: Rename and split top-level consistency checks to match SDM

Rename the top-level consistency check functions to (loosely) align with
the SDM.  Historically, KVM has used the terms "prereq" and "postreq" to
differentiate between consistency checks that lead to VM-Fail and those
that lead to VM-Exit.  The terms are vague and potentially misleading,
e.g. "postreq" might be interpreted as occurring after VM-Entry.

Note, while the SDM lumps controls and host state into a single section,
"Checks on VMX Controls and Host-State Area", split them into separate
top-level functions as the two categories of checks result in different
VM instruction errors.  This split will allow for additional cleanup.

Note #2, "vmentry" is intentionally dropped from the new function names
to avoid confusion with nested_check_vm_entry_controls(), and to keep
the length of the functions names somewhat manageable.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>