firmware: qcom: scm: add OCMEM lock/unlock interface

Add support for the OCMEM lock/unlock interface that is needed by the
On Chip MEMory (OCMEM) that is present on some Snapdragon devices.

Signed-off-by: Rob Clark <robdclark@gmail.com>
[masneyb@onstation.org: ported to latest kernel; minor reformatting.]
Signed-off-by: Brian Masney <masneyb@onstation.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Tested-by: Gabriel Francisco <frc.gabrielgmail.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>