scripts/dtc: dtx_diff: remove broken example from help text

stable inclusion
from stable-v5.10.94
commit 078b5a4498e066fdc9869366d8ffc4d01b1db1c8
bugzilla: https://gitee.com/openeuler/kernel/issues/I531X9

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=078b5a4498e066fdc9869366d8ffc4d01b1db1c8



--------------------------------

commit d8adf5b9 upstream.

dtx_diff suggests to use <(...) syntax to pipe two inputs into it, but
this has never worked: The /proc/self/fds/... paths passed by the shell
will fail the `[ -f "${dtx}" ] && [ -r "${dtx}" ]` check in compile_to_dts,
but even with this check removed, the function cannot work: hexdump will
eat up the DTB magic, making the subsequent dtc call fail, as a pipe
cannot be rewound.

Simply remove this broken example, as there is already an alternative one
that works fine.

Fixes: 10eadc25 ("dtc: create tool to diff device trees")
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reviewed-by: Frank Rowand <frank.rowand@sony.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220113081918.10387-1-matthias.schiffer@ew.tq-group.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>