soc/intel_adsp: Add support for legacy IDC driver for pre-2.5 hardware
soc/intel_adsp: Add support for legacy IDC driver for pre-2.5 hardware

The IDC driver was written for Tiger Lake era devices, but works fine
on the earlier hardware too.  Make it selectable; if you don't
configure IPM_CAVS_IDC, then you get the new driver.

Signed-off-by: Andy Ross <c70f9a6bf6ee0cd69c8af4ce5e6b131945769315@intel.com>

zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr