ipmi: Move BT capabilities detection to the detect call

The capabilities detection was being done as part of the normal
state machine, but it was possible for it to be running while
the upper layers of the IPMI driver were initializing the
device, resulting in error and failure to initialize.

Move the capabilities detection to the the detect function,
so it's done before anything else runs on the device.  This also
simplifies the state machine and removes some code, as a bonus.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Reported-by: Andrew Banman <abanman@hpe.com>
Tested-by: Andrew Banman <abanman@hpe.com>
Cc: <stable@vger.kernel.org>