BugLink: https://bugs.launchpad.net/bugs/1878232

commit 3f1c241f upstream.

SACNT register should be marked volatile since
its WR and RD bits are cleared by SSI after
completing the relevant operation.
This unbreaks AC'97 register access.

Fixes: 05cf2379 ("ASoC: fsl_ssi: Add driver suspend and resume to support MEGA Fast")
Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>