usb: phy: mxs: fix getting wrong state with mxs_phy_is_otg_host()

The function mxs_phy_is_otg_host() will return true if OTG_ID_VALUE is
0 at USBPHY_CTRL register. However, OTG_ID_VALUE will not reflect the real
state if the ID pin is float, such as Host-only or Type-C cases. The value
of OTG_ID_VALUE is always 1 which means device mode.
This patch will fix the issue by judging the current mode based on
last_event. The controller will update last_event in time.

Fixes: 7b09e67 ("usb: phy: mxs: refine mxs_phy_disconnect_line")
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Acked-by: Peter Chen <peter.chen@kernel.org>
Link: https://lore.kernel.org/r/20230627110353.1879477-2-xu.yang_2@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Xu Yang

drivers/usb/phy/phy-mxs-usb.c

@@ -388,14 +388,8 @@ static void __mxs_phy_disconnect_line(struct mxs_phy *mxs_phy, bool disconnect)
 
 static bool mxs_phy_is_otg_host(struct mxs_phy *mxs_phy)
 {
-	void __iomem *base = mxs_phy->phy.io_priv;
-	u32 phyctrl = readl(base + HW_USBPHY_CTRL);
-
-	if (IS_ENABLED(CONFIG_USB_OTG) &&
-			!(phyctrl & BM_USBPHY_CTRL_OTG_ID_VALUE))
-		return true;
-
-	return false;
+	return IS_ENABLED(CONFIG_USB_OTG) &&
+		mxs_phy->phy.last_event == USB_EVENT_ID;
 }
 
 static void mxs_phy_disconnect_line(struct mxs_phy *mxs_phy, bool on)