[PATCH 04/10] parameters: only show possible enumerations if there are any

[Holger Schurig]

Before this patch, "drvinfo fb0" displayed (beside other things):

    Parameters:
      enable: 0
      mode_name: hsd100pxn1 ("hsd100pxn1")

Now it shows:

    Parameters:
      enable: 0
      mode_name: hsd100pxn1