arm/dt: 8974: Update the Low power sequence for L2 SAW

Remove the SPM command from the L2 SAW, that waits for cores to go down
before entering GDHS/power collapse. This command could cause a
deadlock with the Krait SPM command which waits for L2 before resuming
from power collapse.

Change-Id: I4f61873d6c58344323a8b37c79012b9f3a877f59
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>