mmap: remove the IA64-specific vma expansion implementation

With commit cf8e8658 ("arch: Remove Itanium (IA-64) architecture"),
there is no need to keep the IA64-specific vma expansion.

Clean up the IA64-specific vma expansion implementation.

Link: https://lkml.kernel.org/r/20231113124728.3974-1-lukas.bulwahn@gmail.com


Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>