A RAM firmware can only be downloaded if the CS35L56 is currently
running from ROM firmware. The driver must not try to overwrite
the RAM if the CS35L56 is already running from that RAM.

Firmware can be downloaded in these two cases:

- The BIOS has already patched the firmware (secured mode).
  In this case the firmware files will only contain tunings that
  are safe to overwrite.

- The CS35L56 is running the built-in ROM firmware.

After a RAM firmware has been downloaded it can only be cleared by
hard resetting CS35L56. Some systems only hard-reset during
power-on and do not give the driver control of hard reset.
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20230731165726.7940-8-rf@opensource.cirrus.comSigned-off-by: Takashi Iwai <tiwai@suse.de>