ASoC: Remove -dai suffix from i.MX SSI driver

While it is a generic serial port in practice the i.MX SSI is only supported
in Linux as an audio port (the i.MX has dedicated SPI controllers and so on).
This means we don't need to disambiguate against other uses of the hardware
and so can drop the -dai suffix from the driver name which fixes merge
issues with the i.MX tree in -next.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>