KVM: x86: add SMM to the MMU role, support SMRAM address space

This is now very simple to do.  The only interesting part is a simple
trick to find the right memslot in gfn_to_rmap, retrieving the address
space from the spte role word.  The same trick is used in the auditing
code.

The comment on top of union kvm_mmu_page_role has been stale forever,
so remove it.  Speaking of stale code, remove pad_for_nice_hex_output
too: it was splitting the "access" bitfield across two bytes and thus
had effectively turned into pad_for_ugly_hex_output.

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --cc Documentation/virtual/kvm/mmu.txt
Simple merge

diff --cc arch/x86/include/asm/kvm_host.h
Simple merge

diff --cc arch/x86/kvm/mmu.c
Simple merge

diff --cc arch/x86/kvm/mmu_audit.c
Simple merge

diff --cc arch/x86/kvm/x86.c
Simple merge