SoC: rsnd: add interrupt support for SSI BUSIF buffer

SSI BUSIF buffer is possible to overflow or underflow, especially in a
hypervisor environment. If there is no interrupt support, it will eventually
lead to errors in pcm data.
This patch adds overflow and underflow interrupt support for SSI BUSIF buffer.

Reported-by: Chen Li <licheng0822@thundersoft.com>
Signed-off-by: Yongbo Zhang <giraffesnn123@gmail.com>
Tested-by: Chen Li <licheng0822@thundersoft.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/20200512093003.28332-1-giraffesnn123@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>