firmware: qcom_scm: Add calls for csptest

Add SCM calls to check for whether mode switch and secure
watchdog trigger calls are available.
Add SCM call for cpu errata.

Change-Id: Ibe2ccf4d44ce89c342ed3c65bbe6f075f9be8c40
Signed-off-by: Siddharth Gupta <sidgup@codeaurora.org>
Signed-off-by: Elliot Berman <eberman@codeaurora.org>