migration: Fix format in error message

In file_write_ramblock_iov(), "offset" is "uintptr_t" and not
"ram_addr_t". While usually they are both equivalent, this is not the
case with CONFIG_XEN_BACKEND.

Use the right format. This will fix build on 32-bit.

Fixes: f427d90b9898 ("migration/multifd: Support outgoing mapped-ram stream format")
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Link: https://lore.kernel.org/r/20240311123439.16844-1-anthony.perard@citrix.com
Signed-off-by: Peter Xu <peterx@redhat.com>
diff --git a/migration/file.c b/migration/file.c
index 164b079..5054a60 100644
--- a/migration/file.c
+++ b/migration/file.c
@@ -191,7 +191,7 @@
          */
         offset = (uintptr_t) iov[slice_idx].iov_base - (uintptr_t) block->host;
         if (offset >= block->used_length) {
-            error_setg(errp, "offset " RAM_ADDR_FMT
+            error_setg(errp, "offset %" PRIxPTR
                        "outside of ramblock %s range", offset, block->idstr);
             ret = -1;
             break;