firmware: qcom_scm-32: Move SMCCC register filling to qcom_scm_call

firmware: qcom_scm-32: Move SMCCC register filling to qcom_scm_call

Move SMCCC register filling to qcom_scm_call so that __scm_legacy_do
only needs to concern itself with retry mechanism. qcom_scm_call then is
responsible for translating qcom_scm_desc into the complete set of
register arguments and passing onto qcom_scm_call_do.

Tested-by: Brian Masney <masneyb@onstation.org> # arm32
Tested-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Elliot Berman <eberman@codeaurora.org>
Link: https://lore.kernel.org/r/1578431066-19600-13-git-send-email-eberman@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>