usb: dwc3: move generic dwc3 code from gadget into core

A few inits like the scale value or the removal of the DISSCRAMBLE is
done in the gadget code however it touches a general register.
Move this piece to the core.c file since it is likely to be requied by
both, parts of the core (device and host).

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 2175475..6910a2d 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -349,6 +349,29 @@
 
 	dwc3_cache_hwparams(dwc);
 
+	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
+	reg &= ~DWC3_GCTL_SCALEDOWN(3);
+	reg &= ~DWC3_GCTL_DISSCRAMBLE;
+
+	switch (DWC3_GHWPARAMS1_EN_PWROPT(dwc->hwparams.hwparams0)) {
+	case DWC3_GHWPARAMS1_EN_PWROPT_CLK:
+		reg &= ~DWC3_GCTL_DSBLCLKGTNG;
+		break;
+	default:
+		dev_dbg(dwc->dev, "No power optimization available\n");
+	}
+
+	/*
+	 * WORKAROUND: DWC3 revisions <1.90a have a bug
+	 * when The device fails to connect at SuperSpeed
+	 * and falls back to high-speed mode which causes
+	 * the device to enter in a Connect/Disconnect loop
+	 */
+	if (dwc->revision < DWC3_REVISION_190A)
+		reg |= DWC3_GCTL_U2RSTECN;
+
+	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
+
 	ret = dwc3_alloc_event_buffers(dwc, DWC3_EVENT_BUFFERS_SIZE);
 	if (ret) {
 		dev_err(dwc->dev, "failed to allocate event buffers\n");