extcon: intel-cht-wc: Refactor cht_wc_extcon_get_charger()

This is a preparation patch for adding support for registering
a power_supply class device.

Setting usbsrc to "CHT_WC_USBSRC_TYPE_SDP << CHT_WC_USBSRC_TYPE_SHIFT"
will make the following switch-case return EXTCON_CHG_USB_SDP
just as before, so there is no functional change.
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/extcon/extcon-intel-cht-wc.c

@@ -153,14 +153,15 @@ static int cht_wc_extcon_get_charger(struct cht_wc_extcon_data *ext,
 	} while (time_before(jiffies, timeout));
 
 	if (status != CHT_WC_USBSRC_STS_SUCCESS) {
-		if (ignore_errors)
-			return EXTCON_CHG_USB_SDP; /* Save fallback */
-
+		if (!ignore_errors) {
 			if (status == CHT_WC_USBSRC_STS_FAIL)
 				dev_warn(ext->dev, "Could not detect charger type\n");
 			else
 				dev_warn(ext->dev, "Timeout detecting charger type\n");
-		return EXTCON_CHG_USB_SDP; /* Save fallback */
+		}
+
+		/* Safe fallback */
+		usbsrc = CHT_WC_USBSRC_TYPE_SDP << CHT_WC_USBSRC_TYPE_SHIFT;
 	}
 
 	usbsrc = (usbsrc & CHT_WC_USBSRC_TYPE_MASK) >> CHT_WC_USBSRC_TYPE_SHIFT;