firmware: qcom_scm: Add trace points to scm driver

Adding traces to find the arguments passed to secure world
and the values returned.

Change-Id: I6a90f968a05873f0ecbd4a0cc8c85d704e1d64cf
Signed-off-by: Elliot Berman <eberman@codeaurora.org>
Signed-off-by: Siddharth Gupta <sidgup@codeaurora.org>