usb: misc: usb3503: Update error code in print message

'err' is uninitialized, rather print the error code directly.

This also fixes following warning.
drivers/usb/misc/usb3503.c: In function ‘usb3503_probe’:
drivers/usb/misc/usb3503.c:195:11: warning: ‘err’ may be used uninitialized
in this function [-Wmaybe-uninitialized]
    dev_err(dev, "unable to request refclk (%d)\n", err);

Signed-off-by: Tushar Behera <tushar.b@samsung.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>