xen/arm: p2m: Rework the interface of apply_p2m_changes and use typesafe

xen/arm: p2m: Rework the interface of apply_p2m_changes and use typesafe

Most of the callers of apply_p2m_changes have a GFN, a MFN and the
number of frame to change in hand.

Rather than asking each caller to convert the frame to an address,
rework the interfaces to pass the GFN, MFN and the number of frame.

Note that it would be possible to do more clean-up in apply_p2m_changes,
but this will be done in a follow-up series.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>