sif: mmu/fmr: Fix check for page table reusability

sif: mmu/fmr: Fix check for page table reusability

The FMR mapping logic attempts to reuse the page table if memory layout is
sufficiently similar. Currently this optimization is for simplicity
limited to very similar memory layouts and does not handle changes
in the page table level (base page size).

The test for this only considered page sizes going from small to larger
and not the opposite.

This scenario is triggered by NFSoRDMA if the previous use was in
huge page mappable memory and the current use is in more
fragmented memory.

Orabug: 21835309

Signed-off-by: Knut Omang <knut.omang@oracle.com>