sound: Add an ACPI driver for Maxim MAX98357ac

This chip is used on coral and we need to generate ACPI tables for sound
to make it work. Add a driver that does just this (i.e. at present does
not actually support playing sound).

Signed-off-by: Simon Glass <sjg@chromium.org>
[bmeng: Use the correct acpi_irq_polarity enum number]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/sound/Makefile b/drivers/sound/Makefile
index 8c3933a..9b40c80 100644
--- a/drivers/sound/Makefile
+++ b/drivers/sound/Makefile
@@ -17,6 +17,7 @@
 obj-$(CONFIG_SOUND_MAX98088)	+= max98088.o maxim_codec.o
 obj-$(CONFIG_SOUND_MAX98090)	+= max98090.o maxim_codec.o
 obj-$(CONFIG_SOUND_MAX98095)	+= max98095.o maxim_codec.o
+obj-$(CONFIG_SOUND_MAX98357A)	+= max98357a.o
 obj-$(CONFIG_SOUND_INTEL_HDA)	+= hda_codec.o
 obj-$(CONFIG_SOUND_I8254)	+= i8254_beep.o
 obj-$(CONFIG_SOUND_RT5677)	+= rt5677.o