You are right that any value should be OK, and I agree that this is a weird lapse on the
part of the nvidia driver, but I would point out (having had similar trouble myself) that this
is at least documented in the release notes, under "Module Parameters"
The "mtu" module parameter controls the MTU size in bytes. This parameter takes a value between 1500 and 9202, inclusive. By default, a 1500 byte MTU is used. This parameter is only relevant when hardware offload mode is turned on.