migration/multifd: Drop MultiFDSendParams.normal[] array

This array is redundant when p->pages exists.  Now we extended the life of
p->pages to the whole period where pending_job is set, it should be safe to
always use p->pages->offset[] rather than p->normal[].  Drop the array.

Alongside, the normal_num is also redundant, which is the same to
p->pages->num.

This doesn't apply to recv side, because there's no extra buffering on recv
side, so p->normal[] array is still needed.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-6-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>

migration/multifd-zstd.c

@@ -113,6 +113,7 @@ static void zstd_send_cleanup(MultiFDSendParams *p, Error **errp)
  */
 static int zstd_send_prepare(MultiFDSendParams *p, Error **errp)
 {
+    MultiFDPages_t *pages = p->pages;
     struct zstd_data *z = p->data;
     int ret;
     uint32_t i;
@@ -121,13 +122,13 @@ static int zstd_send_prepare(MultiFDSendParams *p, Error **errp)
     z->out.size = z->zbuff_len;
     z->out.pos = 0;
 
-    for (i = 0; i < p->normal_num; i++) {
+    for (i = 0; i < pages->num; i++) {
         ZSTD_EndDirective flush = ZSTD_e_continue;
 
-        if (i == p->normal_num - 1) {
+        if (i == pages->num - 1) {
             flush = ZSTD_e_flush;
         }
-        z->in.src = p->pages->block->host + p->normal[i];
+        z->in.src = p->pages->block->host + pages->offset[i];
         z->in.size = p->page_size;
         z->in.pos = 0;