usb: dwc3: omap: remove unnecessary lock

the lock was only taken inside the hardirq
handler, which runs with IRQs disabled. There's
no chance of any race condition happening, even
on SMP machines. It's safe to remove that
spinlock.
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc3/dwc3-omap.c

@@ -20,7 +20,6 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
-#include <linux/spinlock.h>
 #include <linux/platform_device.h>
 #include <linux/platform_data/dwc3-omap.h>
 #include <linux/pm_runtime.h>
@@ -120,9 +119,6 @@
 #define USBOTGSS_UTMI_OTG_STATUS_VBUSVALID	(1 << 1)
 
 struct dwc3_omap {
-	/* device lock */
-	spinlock_t		lock;
-
 	struct device		*dev;
 
 	int			irq;
@@ -280,8 +276,6 @@ static irqreturn_t dwc3_omap_interrupt(int irq, void *_omap)
 	struct dwc3_omap	*omap = _omap;
 	u32			reg;
 
-	spin_lock(&omap->lock);
-
 	reg = dwc3_omap_read_irqmisc_status(omap);
 
 	if (reg & USBOTGSS_IRQMISC_DMADISABLECLR) {
@@ -322,8 +316,6 @@ static irqreturn_t dwc3_omap_interrupt(int irq, void *_omap)
 
 	dwc3_omap_write_irq0_status(omap, reg);
 
-	spin_unlock(&omap->lock);
-
 	return IRQ_HANDLED;
 }
 
@@ -449,8 +441,6 @@ static int dwc3_omap_probe(struct platform_device *pdev)
 		}
 	}
 
-	spin_lock_init(&omap->lock);
-
 	omap->dev	= dev;
 	omap->irq	= irq;
 	omap->base	= base;