Bluetooth: Fix access to the STK generation methods matrix

The major index of the table is actually the remote I/O capabilities, not
the local ones. As a result, devices with different I/O capabilities
could have used wrong or even unsupported generation methods.

Signed-off-by: Ido Yariv <ido@wizery.com>
CC: Brian Gix <bgix@codeaurora.org>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>