x86/centaur: Use common IA32_FEAT_CTL MSR initialization

Use the recently added IA32_FEAT_CTL MSR initialization sequence to
opportunistically enable VMX support when running on a Centaur CPU.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20191221044513.21680-7-sean.j.christopherson@intel.com