ray_cs: fix array out-of-bounds access

Currently array element org[3] is being accessed, however the array is
only 3 elements in size, so this looks like an off-by-one out-of-bounds
error. Fix this by using org[2], which I believe was the original
intent.

This issue has existed in the driver back in the pre-git days, so no
idea when it was introduced.

Detected by CoverityScan, CID#711344 ("Out-of-bounds read")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>