ASoC: topology: Return bool instead of int

In practice soc_tplg_is_eof() returns boolean value and caller uses the
return value in such way, so convert the function to really do it.

Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20220401120200.4047867-4-amadeuszx.slawinski@linux.intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>