Remove deprecated fs_mgr_overlayfs_required_devices()

It is unused since Ifc8720378259654472d3822e97059b6c366f601d

Bug: 188862155
Test: Build pass
Change-Id: I6304e0dedb36d03a87c556083e937b4a2ce30b1b
Merged-In: I6304e0dedb36d03a87c556083e937b4a2ce30b1b
(cherry picked from commit a07ed968b563f15b35b68c701a97eb239bb34c4c)
diff --git a/fs_mgr/fs_mgr_overlayfs.cpp b/fs_mgr/fs_mgr_overlayfs.cpp
index cb09383..4d32bda 100644
--- a/fs_mgr/fs_mgr_overlayfs.cpp
+++ b/fs_mgr/fs_mgr_overlayfs.cpp
@@ -92,10 +92,6 @@
     return false;
 }
 
-std::vector<std::string> fs_mgr_overlayfs_required_devices(Fstab*) {
-    return {};
-}
-
 bool fs_mgr_overlayfs_setup(const char*, const char*, bool* change, bool) {
     if (change) *change = false;
     return false;
diff --git a/fs_mgr/include/fs_mgr_overlayfs.h b/fs_mgr/include/fs_mgr_overlayfs.h
index d45e2de..6caab1f 100644
--- a/fs_mgr/include/fs_mgr_overlayfs.h
+++ b/fs_mgr/include/fs_mgr_overlayfs.h
@@ -27,7 +27,6 @@
 android::fs_mgr::Fstab fs_mgr_overlayfs_candidate_list(const android::fs_mgr::Fstab& fstab);
 
 bool fs_mgr_overlayfs_mount_all(android::fs_mgr::Fstab* fstab);
-std::vector<std::string> fs_mgr_overlayfs_required_devices(android::fs_mgr::Fstab* fstab);
 bool fs_mgr_overlayfs_setup(const char* backing = nullptr, const char* mount_point = nullptr,
                             bool* change = nullptr, bool force = true);
 bool fs_mgr_overlayfs_teardown(const char* mount_point = nullptr, bool* change = nullptr);