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

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>

tools/vm/slabinfo-gnuplot.sh

@@ -150,7 +150,7 @@ do_preprocess()
 	let lines=3
 	out=`basename "$in"`"-slabs-by-loss"
 	`cat "$in" | grep -A "$lines" 'Slabs sorted by loss' |\
-		egrep -iv '\-\-|Name|Slabs'\
+		grep -E -iv '\-\-|Name|Slabs'\
 		| awk '{print $1" "$4+$2*$3" "$4}' > "$out"`
 	if [ $? -eq 0 ]; then
 		do_slabs_plotting "$out"
@@ -159,7 +159,7 @@ do_preprocess()
 	let lines=3
 	out=`basename "$in"`"-slabs-by-size"
 	`cat "$in" | grep -A "$lines" 'Slabs sorted by size' |\
-		egrep -iv '\-\-|Name|Slabs'\
+		grep -E -iv '\-\-|Name|Slabs'\
 		| awk '{print $1" "$4" "$4-$2*$3}' > "$out"`
 	if [ $? -eq 0 ]; then
 		do_slabs_plotting "$out"