usb: dwc3: dwc3-omap: Do not read DMA status

Commit af566a0b ("usb: dwc3: omap: get rid of dma_status") rendered
reading DMA status from the H/W even more redundant.  The variable hasn't
been read/used since 2016.  Remove the set but unused variable and the call
which populates it.

Fixes the following W=1 warning:

 drivers/usb/dwc3/dwc3-omap.c: In function ‘dwc3_omap_probe’:
 drivers/usb/dwc3/dwc3-omap.c:460:8: warning: variable ‘reg’ set but not used [-Wunused-but-set-variable]
 460 | u32 reg;
 | ^~~

Cc: Felipe Balbi <balbi@kernel.org>
Cc: Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-omap@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200702144625.2533530-9-lee.jones@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/dwc3-omap.c

 // SPDX-License-Identifier: GPL-2.0
-/**
+/*
  * dwc3-omap.c - OMAP Specific Glue layer
  *
  * Copyright (C) 2010-2011 Texas Instruments Incorporated - http://www.ti.com
@@ -457,8 +457,6 @@ static int dwc3_omap_probe(struct platform_device *pdev)
 	int			ret;
 	int			irq;
 
-	u32			reg;
-
 	void __iomem		*base;
 
 	if (!node) {
@@ -503,9 +501,6 @@ static int dwc3_omap_probe(struct platform_device *pdev)
 	dwc3_omap_map_offset(omap);
 	dwc3_omap_set_utmi_mode(omap);
 
-	/* check the DMA Status */
-	reg = dwc3_omap_readl(omap->base, USBOTGSS_SYSCONFIG);
-
 	ret = dwc3_omap_extcon_register(omap);
 	if (ret < 0)
 		goto err1;