OvmfPkg: SmmCpuFeaturesLib: remove unnecessary bits

OvmfPkg: SmmCpuFeaturesLib: remove unnecessary bits

SMRR, MTRR, and SMM Feature Control support is not needed on a virtual
platform.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
[lersek@redhat.com: insert space between ASSERT and (), convert to CRLF,
 refresh against SVN r18958]

Cc: Paolo Bonzini <pbonzini@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19055 6f19259b-4bc3-4df7-8a09-765794883524