USB: isp1362: remove CONFIG_USB_DEBUG dependency

Now that the debugging macros are cleaned up, just rely on the dynamic
debug code in the kernel to do the debug messages for the driver.

This lets debugging be enabled without having to rebuild the driver, an
important thing for users that can not do it.

Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>