ASoC: fsl_ssi: Go back to explicit register defaults

Commit 5c408fee ("ASoC: fsl_ssi: remove explicit register defaults")
causes the driver to fail to probe:

fsl-ssi-dai 2028000.ssi: No cache defaults, reading back from HW
fsl-ssi-dai 2028000.ssi: Failed to init register map
fsl-ssi-dai: probe of 2028000.ssi failed with error -22

, so revert this commit.

Reported-by: Mika Penttilä <mika.penttila@nextfour.com>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>