ASoC: qcom: q6apm: Fix shared memory unmap

Shawn Guo <shengchao.guo@oss.qualcomm.com> says:

Since the early buffer mapping, q6apm maps a front-end's DSP buffers
once in pcm_new() and unmaps them in pcm_free(). The unmap side has a
few problems, which show up when the sound card is unbound and bound
again, e.g. by unbinding and binding any codec on the card:

- The card core removes the components before it frees the PCMs, so
  the topology and its graph info are gone by the time pcm_free()
  tries to unmap. The unmap is silently skipped, the DSP keeps the old
  mapping, and the next bind fails to create the PCM:

    qcom-apm gprsvc:service:2:1: Error (1) Processing 0x0100100c cmd
    snd-sc8280xp sound: ASoC: can't create pcm MultiMedia1 Playback :-22

- Once unmap is actually sent, every command stalls for five seconds,
  because the response handler matches on the wrong opcode:

    qcom-apm gprsvc:service:2:1: CMD timeout for [100100d] opcode

- Unmapping the position buffer clears the circular buffer's handle
  instead of its own.

Patch 1 fixes the unmap response handling, patch 2 makes the position
buffer unmap clear its own handle, and patch 3 moves the unmap to the
APM component's remove callback, before the topology is unloaded.
Patches 1 and 2 go first so that patch 3 does not introduce the five
second stalls.

Tested on Qualcomm Ride board by unbinding and binding the PCM1681
codec.

  echo 0-004c > /sys/bus/i2c/drivers/pcm1681/unbind
  echo 0-004c > /sys/bus/i2c/drivers/pcm1681/bind

Link: https://patch.msgid.link/20261021041044.2080369-1-shengchao.guo@oss.qualcomm.com

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