ASoC: fix unmet dependencies on PPC_BESTCOMM and SND_SOC_AC97_BUS

ASoC: fix unmet dependencies on PPC_BESTCOMM and SND_SOC_AC97_BUS

SND_MPC52xx_SOC_PCM030 and SND_MPC52xx_SOC_EFIKA both select
SND_SOC_MPC5200_AC97 without ensuring its dependency on PPC_BESTCOMM is
met. This causes unmet dependencies such as:

WARNING: unmet direct dependencies detected for SND_SOC_MPC5200_AC97
  Depends on [n]: SOUND [=m] && SND [=m] && SND_SOC [=m] && SND_POWERPC_SOC [=m] && PPC_BESTCOMM [=n]
  Selected by [m]:
  - SND_MPC52xx_SOC_PCM030 [=m] && SOUND [=m] && SND [=m] && SND_SOC [=m] && SND_POWERPC_SOC [=m] && PPC_MPC5200_SIMPLE [=y]

In v1, Rosen pointed out that the import of "mpc5200_dma.h" is actually
unnecessary, and Arnd suggested that the 'select' of SND_SOC_MPC5200_AC97
be changed to 'depends on'.

This resolves all 3 unmet dependencies.

These unmet dependency bugs were detected by kconfirm, a static analysis tool
for Kconfig.

Fixes: a9262c4fd404 ("ASoC: Support for AC97 on Phytec pmc030 base board.")
Fixes: 6ffee43ecf8b ("ASoC: Fabric bindings for STAC9766 on the Efika")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Rosen Penev <rosenp@gmail.com>
Signed-off-by: Julian Braha <julianbraha@gmail.com>
Link: https://patch.msgid.link/20260821175410.179631-1-julianbraha@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>