usb: gadget: f_printer: use non-zero flag for bitwise and

USB_DIR_OUT happens to be zero, so the result of bitwise and is always 0.
Consequently, break will never happen in the SOFT_RESET case.
This patch uses a compatible condition with a non-zero USB_DIR_IN,
which might or might not evaluate to zero.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>