smcinvoke: Call correct apis on basis of device tree entry

Before the advent of cache coherent buffers, cmd_id 0 was
used for invoke functionality that required CMO operations.
On later targets which support cache coherent buffer, a new
cmd_id 0x2 was used that eliminated the need for CMO operations.
However, some targets such as MDM still dont support cache
coherent buffers. So we still have to use older command i.e.
cmd_id 0. This decision is taken by reading the property from
dtsi entry and accordingly call the legcay api inside scm driver.

Change-Id: I71f25ecc21d663331a40ddb8bdfeb75f21449292
Signed-off-by: Anmolpreet Kaur <anmolpre@codeaurora.org>