fs_mgr_overlayfs: MapScratchPartitionIfNeeded always tries to create scratch

Simplify the logic of MapScratchPartitionIfNeeded to just map the
scratch partition unconditionally. If there is a "scratch" logical
partition available, we just assume it must be needed later to
facilitate overlayfs.

Going through the fstab & fs_mgr_overlayfs_candidate_list to determine
if overlayfs is needed or not might be inaccurate as the fstab passed into
MapScratchPartitionIfNeeded is incomplete (it includes only the
"first_stage_mount" entries). So the scratch device might not get created
even though there are some "late mount" partitions that need the scratch
device to facilitate overlayfs.

Bug: 306124139
Test: adb-remount-test
Change-Id: I8590750e822219dec3d7d3c8648e9c9a5a32f68c
diff --git a/fs_mgr/fs_mgr_overlayfs_control.cpp b/fs_mgr/fs_mgr_overlayfs_control.cpp
index 9be236d..33fb080 100644
--- a/fs_mgr/fs_mgr_overlayfs_control.cpp
+++ b/fs_mgr/fs_mgr_overlayfs_control.cpp
@@ -854,21 +854,6 @@
         return;
     }
 
-    bool want_scratch = false;
-    for (const auto& entry : fs_mgr_overlayfs_candidate_list(*fstab)) {
-        if (fs_mgr_is_verity_enabled(entry)) {
-            continue;
-        }
-        if (fs_mgr_overlayfs_already_mounted(fs_mgr_mount_point(entry.mount_point))) {
-            continue;
-        }
-        want_scratch = true;
-        break;
-    }
-    if (!want_scratch) {
-        return;
-    }
-
     if (ScratchIsOnData()) {
         if (auto images = IImageManager::Open("remount", 0ms)) {
             images->MapAllImages(init);