kernel-upgrade: Fix when a linux update already exist.

In this case, it should just be replaced.

Author: mattiaswal

utils/kernel-upgrade.sh

@@ -254,12 +254,22 @@ update_changelog() {
     fi
 
     # Extract just the UNRELEASED section (from start until next version header)
-    UNRELEASED_SECTION=$(sed -n '1,/^\[v[0-9]/p' doc/ChangeLog.md | head -n -1)
+    # Need to find the second [v occurrence (first is UNRELEASED itself, second is previous release)
+    UNRELEASED_SECTION=$(awk '/^\[v[0-9]/ { count++; if (count == 2) exit } { print }' doc/ChangeLog.md)
 
     # Check if there's already a kernel upgrade entry in the UNRELEASED section
     if echo "$UNRELEASED_SECTION" | grep -q "^- Upgrade Linux kernel to"; then
-        # Update existing kernel upgrade line (only first occurrence)
-        sed -i "0,/^- Upgrade Linux kernel to.*/{s|^- Upgrade Linux kernel to.*|- Upgrade Linux kernel to $NEW_VERSION (LTS)|}" doc/ChangeLog.md
+        # Update existing kernel upgrade line in UNRELEASED section only
+        # Find a real release marker (not UNRELEASED), then replace before that
+        awk -v new_version="$NEW_VERSION" '
+            /^\[v[0-9]/ && !/UNRELEASED/ { found_version=1 }
+            /^- Upgrade Linux kernel to/ && !found_version && !replaced {
+                print "- Upgrade Linux kernel to " new_version " (LTS)"
+                replaced=1
+                next
+            }
+            {print}
+        ' doc/ChangeLog.md > doc/ChangeLog.md.tmp && mv doc/ChangeLog.md.tmp doc/ChangeLog.md
         log_info "Updated existing kernel version entry to $NEW_VERSION"
     else
         # Add new kernel upgrade entry after first "### Changes"