plat: imx8mm: Add support for imx8mm lpa

For i.MX8MM low power audio playback, when Linux suspend,
M4 still needs to be active for audio playback, so system
can NOT enter DSM mode but only force A core platform into
STOP mode, PLLs/NoC/DRAM need to be active as well and MU
interrupt wakeup needs to be enabled for waking up Linux
by MU message sent by M4.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Bai Ping <ping.bai@nxp.com>
(cherry picked from commit 7b60954d68e074d6d0d1a6f828f4392cf7c7137d)
4 files changed