We can check if SIIF is enabled by testing the sclp_info struct
instead of testing the sie control block eca variable as that
facility is always enabled if available.

Also let's cleanup all the ipte related struct member accesses
which currently happen by referencing the KVM struct via the
VCPU struct.
Making the KVM struct the parameter to the ipte_* functions
removes one level of indirection which makes the code more readable.
Signed-off-by: NPierre Morel <pmorel@linux.ibm.com>
Reviewed-by: NJanosch Frank <frankja@linux.ibm.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Reviewed-by: NNico Boehr <nrb@linux.ibm.com>
Link: https://lore.kernel.org/all/20220711084148.25017-2-pmorel@linux.ibm.com/Signed-off-by: NJanosch Frank <frankja@linux.ibm.com>