ARM: imx_v6_v7_defconfig: Configure CONFIG_SND_SOC_FSL_ASOC_CARD as module

This option explicitly selects other options, e.g. SND_SOC_FSL_SAI.
These SAI drivers use DMA which in turn is dependent on CONFIG_IMX_SDMA.
SDMA needs a firmware which is not yet present if the driver is built-in.
Thus build CONFIG_SND_SOC_FSL_ASOC_CARD to avoid useless driver probe
deferrals due to missing DMA channels.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>