drm/i915/display: Cleanup intel_phy_is_combo()

Cleanup the intel_phy_is_combo
to accommodate for cases where combo phy is not available.

v2: retain comment that explains DG2 returning false from
intel_phy_is_combo() (Arun)

Cc: Arun R Murthy <arun.r.murthy@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Arun R Murthy <arun.r.murthy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220725225028.98612-1-anusha.srivatsa@intel.com

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

@@ -2082,22 +2082,20 @@ bool intel_phy_is_combo(struct drm_i915_private *dev_priv, enum phy phy)
 {
 	if (phy == PHY_NONE)
 		return false;
-	else if (IS_DG2(dev_priv))
-		/*
-		 * DG2 outputs labelled as "combo PHY" in the bspec use
-		 * SNPS PHYs with completely different programming,
-		 * hence we always return false here.
-		 */
-		return false;
 	else if (IS_ALDERLAKE_S(dev_priv))
 		return phy <= PHY_E;
 	else if (IS_DG1(dev_priv) || IS_ROCKETLAKE(dev_priv))
 		return phy <= PHY_D;
 	else if (IS_JSL_EHL(dev_priv))
 		return phy <= PHY_C;
-	else if (DISPLAY_VER(dev_priv) >= 11)
+	else if (IS_ALDERLAKE_P(dev_priv) || IS_DISPLAY_VER(dev_priv, 11, 12))
 		return phy <= PHY_B;
 	else
+		/*
+		 * DG2 outputs labelled as "combo PHY" in the bspec use
+		 * SNPS PHYs with completely different programming,
+		 * hence we always return false here.
+		 */
 		return false;
 }