bebob: improvement for M-Audio special devices

M-Audio ships some models with heavily-customized firmware.
These models cannot respond against frequent transactions.

This commit adds some waits between transactions for these models.
This commit reduce failure to start/stop streams but it takes more
time to finish processing.

And this commit arranges critical section related to controls.
fireworks/bebob/oxfw: improve PCM constraint

The step of buffer is not effected by constraint of period.
So this commit adds a constraint for the step of buffer.

Additionally expanding the maximum size of buffer/period because
jackd cannot start with devices with maximum channels.
fireworks: change prototype for 'snd_efw_get_multiplier_mode()'