Using negative logic (i.e. fw_security_disabled) is confusing.

Modify the flag to use positive logic (fw_security_enabled).
Signed-off-by: Ohad Sharabi <osharabi@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>