fix(a3k): change fatal error to warning when CM3 reset is not implemented

This allows TF-A's a3700_system_reset() function to try Warm reset
method when CM3 reset method is not implemented by WTMI firmware.

Signed-off-by: Pali Rohár <pali@kernel.org>
Change-Id: I7303197373e1a8ca5a44ba0b1e90b48855d6c0c3
1 file changed