fix: remove trailing newline in packetparser

Fix trailing blank line at end of file flagged by gofmt. Keep _cprog
blank import unchanged from main so only-new-issues suppresses the
typecheck error.

Signed-off-by: Quang Nguyen <nguyenquang@microsoft.com>

Author: nddq

pkg/plugin/packetparser/packetparser_linux.go

@@ -731,4 +731,3 @@ func absPath() (string, error) {
 	dir := path.Dir(filename)
 	return dir, nil
 }
-