ASoC: sound/soc/sof/: fix kconfig dependency warning

ASoC: sound/soc/sof/: fix kconfig dependency warning

Fix kconfig warning for unmet dependency for IOSF_MBI when
PCI is not set/enabled.  Fixes this warning:

WARNING: unmet direct dependencies detected for IOSF_MBI
  Depends on [n]: PCI [=n]
  Selected by [y]:
  - SND_SOC_SOF_ACPI [=y] && SOUND [=y] && !UML && SND [=y] && SND_SOC [=y] && SND_SOC_SOF_TOPLEVEL [=y] && (ACPI [=y] || COMPILE_TEST [=n]) && X86 [=y]

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: alsa-devel@alsa-project.org
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>