tools/vm/slabinfo-gnuplot: use "grep -E" instead of "egrep"

stable inclusion
from stable-v5.10.158
commit 6ddf788400dd3f5b75f807164bf91a59ee6b3b32
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7NTXH

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6ddf788400dd3f5b75f807164bf91a59ee6b3b32

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

commit a435874b upstream.

The latest version of grep claims the egrep is now obsolete so the build
now contains warnings that look like:

	egrep: warning: egrep is obsolescent; using grep -E

fix this up by moving the related file to use "grep -E" instead.

  sed -i "s/egrep/grep -E/g" `grep egrep -rwl tools/vm`

Here are the steps to install the latest grep:

  wget http://ftp.gnu.org/gnu/grep/grep-3.8.tar.gz
  tar xf grep-3.8.tar.gz
  cd grep-3.8 && ./configure && make
  sudo make install
  export PATH=/usr/local/bin:$PATH

Link: https://lkml.kernel.org/r/1668825419-30584-1-git-send-email-yangtiezhu@loongson.cn


Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>