bpftool: Add bash completion for token argument

This commit updates the bash completion script with the
new token argument.
$ bpftool token
help  list  show

Reviewed-by: Quentin Monnet <[email protected]>
Signed-off-by: Tao Chen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>

Author: Tao Chen

tools/bpf/bpftool/bash-completion/bpftool

@@ -1215,6 +1215,17 @@ _bpftool()
                     ;;
             esac
             ;;
+        token)
+            case $command in
+               show|list)
+                   return 0
+                   ;;
+               *)
+                   [[ $prev == $object ]] && \
+                       COMPREPLY=( $( compgen -W 'help show list' -- "$cur" ) )
+                   ;;
+            esac
+            ;;
     esac
 } &&
 complete -F _bpftool bpftool