usb: gadget: fusb300_udc: add FUSB300_EPSET0_STL_CLR for clearing EP0 stall

The final version of fusb300 controller adds EPSET0_STL_CLR
for clearing EP0 stall and also removes EPSET0_EPn_TX0BYTE.

fusb300_udc driver is tested on FARADAY platform a369 with
FUSB300 FPGA v1.8

Signed-off-by: Yuan-Hsin Chen <yhchen@faraday-tech.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/gadget/fusb300_udc.c b/drivers/usb/gadget/fusb300_udc.c
index d053553..db0d291 100644
--- a/drivers/usb/gadget/fusb300_udc.c
+++ b/drivers/usb/gadget/fusb300_udc.c
@@ -394,7 +394,7 @@
 
 	if (reg & FUSB300_EPSET0_STL) {
 		printk(KERN_DEBUG "EP%d stall... Clear!!\n", ep);
-		reg &= ~FUSB300_EPSET0_STL;
+		reg |= FUSB300_EPSET0_STL_CLR;
 		iowrite32(reg, fusb300->reg + FUSB300_OFFSET_EPSET0(ep));
 	}
 }