KVM: PPC: BOOK3S: HV: Use base page size when comparing against slb value

With guests supporting Multiple page size per segment (MPSS),
hpte_page_size returns the actual page size used. Add a new function to
return base page size and use that to compare against the the page size
calculated from SLB. Without this patch a hpte lookup can fail since
we are comparing wrong page size in kvmppc_hv_find_lock_hpte.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

diff --cc arch/powerpc/include/asm/kvm_book3s_64.h
Simple merge

diff --cc arch/powerpc/kvm/book3s_64_mmu_hv.c
Simple merge

diff --cc arch/powerpc/kvm/book3s_hv_rm_mmu.c
Simple merge