firmware: cs_dsp: Remove async regmap writes

firmware: cs_dsp: Remove async regmap writes

Change calls to async regmap write functions to use the normal
blocking writes so that the cs35l56 driver can use spi_bus_lock() to
gain exclusive access to the SPI bus.

As this is part of a fix, it makes only the minimal change to swap the
functions to the blocking equivalents. There's no need to risk
reworking the buffer allocation logic that is now partially redundant.

The async writes are a 12-year-old workaround for inefficiency of
synchronous writes in the SPI subsystem. The SPI subsystem has since
been changed to avoid the overheads, so this workaround should not be
necessary.

The cs35l56 driver needs to use spi_bus_lock() prevent bus activity
while it is soft-resetting the cs35l56. But spi_bus_lock() is
incompatible with spi_async() calls, which will fail with -EBUSY.

Fixes: 8a731fd37f8b ("ASoC: cs35l56: Move utility functions to shared file")
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://patch.msgid.link/20250225131843.113752-2-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>