drm/i915/skl: enable DDI-E hotplug

v2: fix one error found by checkpath.pl
v3: Add one ignored break for switch-case. DDI-E hotplug
    function doesn't work after updating drm-intel tree,
    I checked the code and found this missing which isn't
    the root cause for broke DDI-E hp.  The broken
    DDI-E hp function is fixed by "Adding DDI_E power
    well domain".

Signed-off-by: Xiong Zhang <xiong.y.zhang@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Tested-by: Timo Aaltonen <timo.aaltonen@canonical.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_hotplug.c

@@ -91,6 +91,9 @@ bool intel_hpd_pin_to_port(enum hpd_pin pin, enum port *port)
 	case HPD_PORT_D:
 		*port = PORT_D;
 		return true;
+	case HPD_PORT_E:
+		*port = PORT_E;
+		return true;
 	default:
 		return false;	/* no hpd */
 	}