firmware: qcom_scm-64: Move svc/cmd/owner into qcom_scm_desc

Service, command, and owner IDs are all part of qcom_scm_desc struct and
have no special reason to be a function argument (or hard-coded in the
case of owner). Moving them to be part of qcom_scm_desc struct improves
readability.

Change-Id: I422e5b0c2c117ff4eafc80f16b34874ff86643d3
Signed-off-by: Elliot Berman <eberman@codeaurora.org>