qcom: scm: provide scm_is_secure_device() api

Add new scm_is_secure_device() API, so that
all platform drivers can check and take appropriate
action for secure and non-secure devices.

Change-Id: I5569f4aaf4bcbec2922a7745ec0fdc1ab423cc23
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>