[Sound-open-firmware] Fallback on failed custom firmware loading

[Curtis Malainey]

Hello Pierre,

I was wondering if this feature would be ok with you. We are working
to start switching out various firmware files using command line boot
params. Given we are doing this in AP firmware, we have no indication
of what is in the OS and if the device has been loaded with a
non-standard image. We clearly don't want to break audio for users who
are running vanilla linux on these machines. So what my proposal is,
if a firmware/topology path is passed in via module params is not
found, that we fall back to the next method (dmi check) and lastly
using the default rather than doing a one shot method. What are your
thoughts here?