rsxx: Fix possible kernel panic with invalid config.

This patch fixes a possible Kernel Panic on driver load if
the configuration on the card is messed up or not yet set.
The driver could possible give a 32 bit unsigned all Fs to
the kernel as the device's block size.

Now we only write the block size to the kernel if the
configuration from the card is valid.

Also, driver version is being updated.

Signed-off-by: Philip J Kelleher <pjk1939@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>