usb: musb: core: fix order of arguments to ulpi write callback

There is a bit of a mess in the order of arguments to the ulpi write
callback. There is

	int ulpi_write(struct ulpi *ulpi, u8 addr, u8 val)

in drivers/usb/common/ulpi.c;

	struct usb_phy_io_ops {
		...
		int (*write)(struct usb_phy *x, u32 val, u32 reg);
	}

in include/linux/usb/phy.h.

The callback registered by the musb driver has to comply to the latter,
but up to now had "offset" first which effectively made the function
broken for correct users. So flip the order and while at it also
switch to the parameter names of struct usb_phy_io_ops's write.

Fixes: ffb865b1

 ("usb: musb: add ulpi access operations")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>