ARM: shmobile: multiplatform: add AK4642 support on defconfig

AK4642 is well used audio codec on Renesas reference board

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/configs/shmobile_defconfig

@@ -126,6 +126,7 @@ CONFIG_SND=y
 CONFIG_SND_SOC=y
 CONFIG_SND_SOC_SH4_FSI=y
 CONFIG_SND_SOC_RCAR=y
+CONFIG_SND_SOC_AK4642=y
 CONFIG_SND_SOC_WM8978=y
 CONFIG_USB=y
 CONFIG_USB_EHCI_HCD=y