usb: ehci: mxs: fix swapped argument in ehci_writel()

usb: ehci: mxs: fix swapped argument in ehci_writel()

ehci_writel() swaps the arguments for address and value. One call
in ehci-mxs ignores that.

This fixes the warning:

drivers/usb/host/ehci-mxs.c: In function ?ehci_hcd_stop?:
drivers/usb/host/ehci-mxs.c:159:19: error: initialization makes integer from pointer without a cast [-Werror=int-conversion]
  ehci_writel(tmp, &hcor->or_usbcmd);
                   ^
arch/arm/include/asm/io.h:117:34: note: in definition of macro ?writel?
 #define writel(v,c) ({ u32 __v = v; __iowmb(); __arch_putl(__v,c); __v; })
                                  ^
drivers/usb/host/ehci-mxs.c:159:2: note: in expansion of macro ?ehci_writel?
  ^~~~~~~~~~~

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>