qcom: scm: Add SCM warmboot support for quad core SoCs

Quad core SoCs like APQ8074, APQ8064, APQ8084 need SCM support set up
warm boot addresses in the Secure Monitor. Extend the SCM flags to
support warm boot addresses for secondary cores.

We do not need to export the warmboot flags. Move them into the
implementation file.

Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>