drm/edid: Add the missing "Hz" to VIC 58,59 comment

All the VICs apart from 58 and 59 have the word "Hz" included in the
comment. Include it for 59 and 59 as well.

Cc: Shashank Sharma <shashank.sharma@intel.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1478177609-16762-1-git-send-email-ville.syrjala@linux.intel.com