usb: typec: altmodes/displayport: Use proper macro for pin assignment check

While looking at the DP configuration VDO to determine the peripheral
configuration, the spec (Table 8-5: DisplayPort Configurations, VESA
DisplayPort Alt Mode Standard v2.0) lists the options as "UFP_U as a DP
Source/Sink Device".

So, use the correct macro while performing this check. Effectively it's
the same as the existing code, but the proposed macro describes the
state a little better.

No functional changes introduced.

Cc: Heikki Krogerus <[e-mail]>
Signed-off-by: Prashant Malani <[e-mail]>
Reviewed-by: Benson Leung <[e-mail]>
Reviewed-by: Heikki Krogerus <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/typec/altmodes/displayport.c

···
  */
 static u8 get_current_pin_assignments(struct dp_altmode *dp)
 {
-	if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_DFP_D)
+	if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_UFP_U_AS_DFP_D)
 		return DP_CAP_PIN_ASSIGN_DFP_D(dp->alt->vdo);
 	else
 		return DP_CAP_PIN_ASSIGN_UFP_D(dp->alt->vdo);