fs/adfs: remove unneeded variable make code cleaner

Return value directly instead of taking this in a variable.

Link: https://lkml.kernel.org/r/20211210023211.424609-1-chi.minghao@zte.com.cn
Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
Reported-by: Zeal Robot <zealci@zte.com.cm>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>