KVM: SEV: Consolidate the SEV policy bits in a single header file

KVM: SEV: Consolidate the SEV policy bits in a single header file

Consolidate SEV policy bit definitions into a single file. Use
include/linux/psp-sev.h to hold the definitions and remove the current
definitions from the arch/x86/kvm/svm/sev.c and arch/x86/include/svm.h
files.

No functional change intended.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://patch.msgid.link/d9639f88a0b521a1a67aeac77cc609fdea1f90bd.1761593632.git.thomas.lendacky@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>