msm: scm: Add a feat version query API

Some users of SCM need to detect features and also detect if
those features have certain versions available. Most notably the
jtag save restore code needs to detect if the secure environment
supports save and restore of jtag state so that it can skip doing
its own save and restore.

Add this API so that the code can work with either version of the
secure code.

Change-Id: Ice34a894b1eb48cbf741138858e68c91c6bdd98d
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>