KVM: SVM: Move EFER and MSR constants to generic x86 code

MSR_EFER_SVME_MASK, MSR_VM_CR and MSR_VM_HSAVE_PA are set in KVM
specific headers. Linux does have nice header files to collect
EFER bits and MSR IDs, so IMHO we should put them there.

While at it, I also changed the naming scheme to match that
of the other defines.

(introduced in v6)

Acked-by: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>