LAVA Configs: Update Log String to Be Matched

TF-M has made some modification on logs.
"[Sec Thread] Secure image initializing!" was removed in some configs.
Target log string to be matched by LAVA server should also be updated.

Signed-off-by: Xinyu Zhang <xinyu.zhang@arm.com>
Change-Id: I7d71461f020801cb9d07af7191dcc0f0e66fcd5b
1 file changed