ASoC: sh: fsi: use simple-card instead of fsi-ak4642

This patch uses simple-card driver instead of fsi-ak4642 on each board.
To select AK4642 driver, each boards select it on Kconfig.

This patch removes fsi-ak4642 driver which is no longer needed

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/arch/sh/boards/Kconfig b/arch/sh/boards/Kconfig
index d893411..0da49f3 100644
--- a/arch/sh/boards/Kconfig
+++ b/arch/sh/boards/Kconfig
@@ -54,6 +54,7 @@
 	select SOLUTION_ENGINE
 	depends on CPU_SUBTYPE_SH7724
 	select ARCH_REQUIRE_GPIOLIB
+	select SND_SOC_AK4642 if SND_SIMPLE_CARD
 	help
 	  Select 7724 SolutionEngine if configuring for a Hitachi SH7724
 	  evaluation board.