usb: chipidea: Fix Internal error: : 808 [#1] ARM related to STS flag

* init the sts flag to 0 (missed)
* fix write the real bit not sts value
* Set PORTCS_STS and DEVLC_STS only if sts = 1

[Peter Chen: This one and the next patch fix the problem occurred imx27
and imx31, and imx27 and imx31 usb support are enabled until 3.14, so
these two patches isn't needed for -stable]
Signed-off-by: Chris Ruehl <chris.ruehl@gtsys.com.hk>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/core.c

@@ -236,7 +236,7 @@ static int hw_device_init(struct ci_hdrc *ci, void __iomem *base)
 
 static void hw_phymode_configure(struct ci_hdrc *ci)
 {
-	u32 portsc, lpm, sts;
+	u32 portsc, lpm, sts = 0;
 
 	switch (ci->platdata->phy_mode) {
 	case USBPHY_INTERFACE_MODE_UTMI:
@@ -266,10 +266,12 @@ static void hw_phymode_configure(struct ci_hdrc *ci)
 
 	if (ci->hw_bank.lpm) {
 		hw_write(ci, OP_DEVLC, DEVLC_PTS(7) | DEVLC_PTW, lpm);
-		hw_write(ci, OP_DEVLC, DEVLC_STS, sts);
+		if (sts)
+			hw_write(ci, OP_DEVLC, DEVLC_STS, DEVLC_STS);
 	} else {
 		hw_write(ci, OP_PORTSC, PORTSC_PTS(7) | PORTSC_PTW, portsc);
-		hw_write(ci, OP_PORTSC, PORTSC_STS, sts);
+		if (sts)
+			hw_write(ci, OP_PORTSC, PORTSC_STS, PORTSC_STS);
 	}
 }