a8k: pm: extend MSS_TRIGGER_TIMEOUT

a8k: pm: extend MSS_TRIGGER_TIMEOUT

Very rarely, during cpuidle operations the following error
is seen: "PM MSG Trigger Timeout".
This is caused by slow handling of message interrutps
in the PM FW running on CM3 (under heavy PM operation load).

This is not a real issue, so we extend the timeout to
avoid the error prints.

Change-Id: I92fd6f2ff1ddf208b216c123880ded28a00b6e0e
Signed-off-by: Igal Liberman <igall@marvell.com>
Reviewed-on: http://vgitil04.il.marvell.com:8080/59670
Reviewed-by: Kostya Porotchkin <kostap@marvell.com>
Tested-by: iSoC Platform CI <ykjenk@marvell.com>