video: udlfb: Fix read EDID timeout

While usb_control_msg function expects timeout in miliseconds, a value
of HZ is used. Replace it with USB_CTRL_GET_TIMEOUT and also fix error
message which looks like:
udlfb: Read EDID byte 78 failed err ffffff92
as error is either negative errno or number of bytes transferred use %d
format specifier.

Returned EDID is in second byte, so return error when less than two bytes
are received.

Fixes: 18dffdf8 ("staging: udlfb: enhance EDID and mode handling support")
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>