UBUNTU: [Packaging] Remove all custom retpoline-extract code

BugLink: https://bugs.launchpad.net/bugs/2046440

Now that retpoline & SLS mitigration checks are enforced during build
via objtool patch, drop all custom retpoline packaging, abi files, and
checks.

Signed-off-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>

debian/scripts/checks/final-checks

@@ -40,13 +40,6 @@ abi_check()
 	then
 		failure "$arch/$flavour ABI modules file missing"
 	fi
-
-	if [ ! -f "$abidir/$flavour.retpoline" ] && \
-	   [ ! -f "$abidir/$flavour.ignore.retpoline" ] && \
-	   [ ! -f "$abidir/ignore.retpoline" ]
-	then
-		failure "$arch/$flavour ABI retpoline file missing"
-	fi
 }
 
 abi_version="$debian/abi/version"

debian/scripts/checks/retpoline-check

@@ -1,52 +0,0 @@
-#!/bin/bash
-
-flavour="$1"
-prev_abidir="$2"
-curr_abidir="$3"
-
-skipretpoline=${4:-}
-case "${skipretpoline,,}" in
-	1|true|yes) skipretpoline=true ;;
-	*) skipretpoline=false ;;
-esac
-
-echo "II: Checking retpoline indirections for $flavour...";
-
-if [ "$skipretpoline" = 'true' ]; then
-	echo "manual request ignoring retpoline delta"
-fi
-
-if [ -f "$prev_abidir/ignore.retpoline" -o \
-     -f "$prev_abidir/$flavour.ignore.retpoline" ]; then
-	echo "explicitly ignoring retpoline delta"
-	skipretpoline='true'
-fi
-
-prev="$prev_abidir/$flavour.retpoline"
-curr="$curr_abidir/$flavour.retpoline"
-if [ ! -f "$prev" ]; then
-	echo "previous retpoline file missing!"
-	echo "   $prev"
-	prev="/dev/null"
-fi
-if [ ! -f "$curr" ]; then
-	echo "current retpoline file missing!"
-	echo "   $curr"
-	curr="/dev/null"
-fi
-
-echo "II: retpoline delta in this package..."
-rc=0
-diff -u "$prev" "$curr" || true
-count=$( diff -u "$prev" "$curr" | grep '^+[^+]' | wc -l )
-if [ "$count" != 0 ]; then
-	rc=1
-	echo "WW: $count new retpoline sequences detected"
-fi
-
-echo "II: Done";
-if [ "$skipretpoline" = 'true' -a "$rc" -ne 0 ]; then
-	echo "II: ignoring errors"
-	exit 0
-fi
-exit "$rc"