xhci: replace xhci_writel() with writel()

Function xhci_writel() is used to write a 32bit value in xHC registers residing
in MMIO address space. It takes as first argument a pointer to the xhci_hcd
although it does not use it. xhci_writel() internally simply calls writel().
This creates an illusion that xhci_writel() is an xhci specific function that
has to be called in a context where a pointer to xhci_hcd is available.

Remove xhci_writel() wrapper function and replace its calls with calls to
writel() to make the code more straight-forward.

Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>

drivers/usb/host/xhci-mem.c

@@ -2254,7 +2254,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 	val |= (val2 & ~HCS_SLOTS_MASK);
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
 			"// Setting Max device slots reg = 0x%x.", val);
-	xhci_writel(xhci, val, &xhci->op_regs->config_reg);
+	writel(val, &xhci->op_regs->config_reg);
 
 	/*
 	 * Section 5.4.8 - doorbell array must be
@@ -2388,7 +2388,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
 			"// Write ERST size = %i to ir_set 0 (some bits preserved)",
 			val);
-	xhci_writel(xhci, val, &xhci->ir_set->erst_size);
+	writel(val, &xhci->ir_set->erst_size);
 
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
 			"// Set ERST entries to point to event ring.");
@@ -2434,7 +2434,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 	temp = readl(&xhci->op_regs->dev_notification);
 	temp &= ~DEV_NOTE_MASK;
 	temp |= DEV_NOTE_FWAKE;
-	xhci_writel(xhci, temp, &xhci->op_regs->dev_notification);
+	writel(temp, &xhci->op_regs->dev_notification);
 
 	return 0;