fixup! rust: io_pgtable: Add io_pgtable abstraction

kernel API change: add optional alloc/free function pointers to bindings::io_pgtable_cfg

Signed-off-by: Janne Grunau <j@jannau.net>
(cherry picked from commit 8862278 https://github.com/AsahiLinux/linux)
Signed-off-by: John Cabaj <john.cabaj@canonical.com>

Author: jannau

rust/kernel/io_pgtable.rs

@@ -124,6 +124,8 @@ pub trait IoPageTable: crate::private::Sealed {
             coherent_walk: config.coherent_walk,
             tlb: &Self::FLUSH_OPS,
             iommu_dev: dev.raw_device(),
+            alloc: None,
+            free: None,
             __bindgen_anon_1: unsafe { mem::zeroed() },
         };