objcopy.c: Re-indent slim LTO IR comment

Re-indent slim LTO IR comment in

commit 9b383903e73cd01f2fbe9728d0c31fea765ba8d6
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Tue Aug 12 12:02:08 2025 -0700

    strip: Treat slim GCC/LLVM IR objects the same

	PR binutils/33271
	* objcopy.c (copy_file): Re-indent slim LTO IR comment.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>