Allow the component debugfs_prefix to be set from
snd_soc_component_driver. First use case is avoiding a duplicate
debugfs entry error in case a device has multiple components
which have the same name therefore.

Note that we don't set component->debugfs_prefix if it's set already.
That's needed because partially component->debugfs_prefix is set
before calling snd_soc_component_initialize().
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/d18bff6a-1df1-5f95-0cf8-10dbaa62d7be@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>