POSIX Device: Fix IOCTL interface

src/drivers/device/device_posix.cpp

@@ -96,7 +96,7 @@ Device::dev_write(unsigned offset, void *data, unsigned count)
 }
 
 int
-Device::dev_ioctl(unsigned operation, unsigned &arg)
+Device::dev_ioctl(unsigned operation, unsigned arg)
 {
 	switch (operation) {
 	case DEVIOCGDEVICEID:

src/drivers/device/vdev.h

@@ -128,7 +128,7 @@ public:
 	 * @param arg           An argument to the operation.
 	 * @return              Negative errno on error, OK or positive value on success.
 	 */
-	virtual int     dev_ioctl(unsigned operation, unsigned &arg);
+	virtual int     dev_ioctl(unsigned operation, unsigned arg);
 
 	/*
 	  device bus types for DEVID