ASoC: rockchip: i2s-tdm: Use param rate if not provided by set_sysclk

ASoC: rockchip: i2s-tdm: Use param rate if not provided by set_sysclk

Drivers will not always call set_sysclk() for all clocks, especially when
default mclk-fs can be used.
When that is the case, use the clock rate set in the params multiplied by the
default mclk-fs.

Fixes: 5323186e2e8d ("ASoC: rockchip: i2s_tdm: Re-add the set_sysclk callback")
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Reported-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Link: https://patch.msgid.link/20260218201834.924358-1-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>