drm/i915: prefer 3-letter acronym for cannonlake

We are currently using a mix of platform name and acronym to name the
functions. Let's prefer the acronym as it should be clear what platform
it's about and it's shorter, so it doesn't go over 80 columns in a few
cases. This converts cannonlake to cnl where appropriate.
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Acked-by: Jani Nikula <jani.nikula@linux.intel.com>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191224084012.24241-5-lucas.demarchi@intel.com

drivers/gpu/drm/i915/display/intel_display.c

@@ -10424,8 +10424,7 @@ static int hsw_crtc_compute_clock(struct intel_crtc *crtc,
 	return 0;
 }
 
-static void cannonlake_get_ddi_pll(struct drm_i915_private *dev_priv,
-				   enum port port,
+static void cnl_get_ddi_pll(struct drm_i915_private *dev_priv, enum port port,
 			    struct intel_crtc_state *pipe_config)
 {
 	enum intel_dpll_id id;
@@ -10728,7 +10727,7 @@ static void hsw_get_ddi_port_state(struct intel_crtc *crtc,
 	if (INTEL_GEN(dev_priv) >= 11)
 		icelake_get_ddi_pll(dev_priv, port, pipe_config);
 	else if (IS_CANNONLAKE(dev_priv))
-		cannonlake_get_ddi_pll(dev_priv, port, pipe_config);
+		cnl_get_ddi_pll(dev_priv, port, pipe_config);
 	else if (IS_GEN9_BC(dev_priv))
 		skl_get_ddi_pll(dev_priv, port, pipe_config);
 	else if (IS_GEN9_LP(dev_priv))