USB: xhci: fix some compiler warnings in xhci.h

This fixes the warning:
drivers/usb/host/xhci.h:1083: warning: passing argument 1 of ‘xhci_to_hcd’ discards qualifiers from pointer target type
drivers/usb/host/xhci.h:1083: warning: passing argument 1 of ‘xhci_to_hcd’ discards qualifiers from pointer target type

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/xhci.h

@@ -1068,12 +1068,13 @@ static inline unsigned int xhci_readl(const struct xhci_hcd *xhci,
 {
 	return readl(regs);
 }
-static inline void xhci_writel(const struct xhci_hcd *xhci,
+static inline void xhci_writel(struct xhci_hcd *xhci,
 		const unsigned int val, __u32 __iomem *regs)
 {
 	if (!in_interrupt())
-		xhci_dbg(xhci, "`MEM_WRITE_DWORD(3'b000, 32'h%0x, 32'h%0x, 4'hf);\n",
-				(unsigned int) regs, val);
+		xhci_dbg(xhci,
+			 "`MEM_WRITE_DWORD(3'b000, 32'h%p, 32'h%0x, 4'hf);\n",
+			 regs, val);
 	writel(val, regs);
 }