macaudio: Fix missing kconfig requirement

Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>

Author: WhatAmISupposedToPutHere

sound/soc/apple/Kconfig

@@ -19,6 +19,7 @@ config SND_SOC_APPLE_MACAUDIO
 	select SND_SOC_TAS2770 if I2C
 	select SND_SOC_CS42L83 if I2C
 	select SND_SOC_CS42L84 if I2C
+	select REGULATOR_FIXED_VOLTAGE if REGULATOR
 	help
 	  This option enables an ASoC machine-level driver for Apple Silicon Macs
 	  and it also enables the required SoC and codec drivers for overall