ASoC: spacemit: move hw constraints from hw_params to startup

ASoC: spacemit: move hw constraints from hw_params to startup

Hardware constraints should be applied in the startup callback rather
than hw_params, as hw_params may be called too late for the constraints
to take effect properly.

Move the channel count and format constraints for I2S and DSP_A/DSP_B
modes into a new startup callback. This also tightens the I2S mode
channel constraint from 1-2 to exactly 2, matching the actual hardware
behavior.

Signed-off-by: Troy Mitchell <troy.mitchell@linux.spacemit.com>
Link: https://patch.msgid.link/20260429-k3-i2s-v1-2-2fe99db11ecb@linux.spacemit.com
Signed-off-by: Mark Brown <broonie@kernel.org>