RTS and the GPL

Linux with static linked driver is derived work and must all be GPL.
Linux with a dynamical linked driver is essential the same thing and must therefore also be GPL.

Notice the explicit difference between GPL and LGPL.

Thus shipping a system with Linux and a propriatary driver is a GPL violation.

Workaround:
You can ship the system without the driver and then ask the customer to download and install the driver - as is done with the NVIDIA drivers.