qcom: scm: Define new api to support legacy functionality of smcinvoke

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. Introducing a new API to take care of both targets i.e. which supports
cache coherency and non-cache coherency.

Change-Id: If044725616cde01274a19b0310e309186f7d782b
Signed-off-by: Anmolpreet Kaur <anmolpre@codeaurora.org>