ASoC: Intel: fix ACPI probe regression with Atom DPCM driver

The commit 95f09801
"ASoC: Intel: Move apci find machine routines"

introduced a regression in ACPI probe of the DPCM driver.
Fix by conditionally compiling sst-acpi when the DPCM driver
is not selected
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/common/Makefile

 snd-soc-sst-dsp-objs := sst-dsp.o
+ifneq ($(CONFIG_SND_SST_IPC_ACPI),)
+snd-soc-sst-acpi-objs := sst-match-acpi.o
+else
 snd-soc-sst-acpi-objs := sst-acpi.o sst-match-acpi.o
+endif
+
 snd-soc-sst-ipc-objs := sst-ipc.o
 
 snd-soc-sst-dsp-$(CONFIG_DW_DMAC_CORE) += sst-firmware.o