snd_efw: fix infinite loop to read transaction generated by kernel side
snd_efw: fix infinite loop to read transaction generated by kernel side

ALSA's Fireworks driver has an option to store the result of transactions
generated by kernel side. But in this case, current libhinawa
implementation causes infinite loop.

This commit fixes this bug to ignore such transaction.

takaswie/libhinawa,takaswie/libhinawa