west: sign: add support for NXP i.MX8QXP board
west: sign: add support for NXP i.MX8QXP board

Add support for signing i.MX8QXP SOF with Zephyr images with rimage.

i.MX8QXP and i.MX8QM have the same board-level definitions,
so we use the generic imx8.

Signed-off-by: Iuliana Prodan <7b818b64817a481630781727960c0e7b728288f0@nxp.com>

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