ntfs3: fix double free of sbi->options->nls and clarify ownership of fc->fs_private

commit 02f312754c87 ("ntfs3: fix use-after-free of sbi->options in cmp_fnames") introduced a use-after-free bug
due to improper handling of sbi->options in error paths. This resulted in crashes when superblock cleanup
is performed in ntfs_put_super.

This patch ensures that the options structure and its subfields are properly freed, preventing the memory
corruption and use-after-free errors.

Fixes: 02f312754c87 ("ntfs3: fix use-after-free of sbi->options in cmp_fnames")
Reported-by: [e-mail]
Closes: https://syzkaller.appspot.com/bug?extid=cc433e4cd6d54736bf80
Signed-off-by: YangWen <[e-mail]>
[[e-mail]: added fixes and closes tags]
Signed-off-by: Konstantin Komarov <[e-mail]>

fs/ntfs3/super.c

···
 
 	if (sbi->options) {
 		unload_nls(sbi->options->nls);
-		kfree(sbi->options->nls);
+		kfree(sbi->options->nls_name);
 		kfree(sbi->options);
 		sbi->options = NULL;
 	}
···
 		}
 	}
 	sbi->options = options;
+	fc->fs_private = NULL;
 	sb->s_flags |= SB_NODIRATIME;
 	sb->s_magic = 0x7366746e; // "ntfs"
 	sb->s_op = &ntfs_sops;
···
 out:
 	if (sbi && sbi->options) {
 		unload_nls(sbi->options->nls);
-		kfree(sbi->options->nls);
+		kfree(sbi->options->nls_name);
 		kfree(sbi->options);
 		sbi->options = NULL;
 	}