xen/arm: mm: Re-implement setup_frame_table_mappings() with map_pages_to_xen()

xen/arm: mm: Re-implement setup_frame_table_mappings() with map_pages_to_xen()

Now that map_pages_to_xen() has been extended to support 2MB mappings,
we can replace the create_mappings() call by map_pages_to_xen() call.

This has the advantage to remove the differences between 32-bit and
64-bit code.

Lastly remove create_mappings() as there is no more callers.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
Tested-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>