firmware: qcom_scm: Remove thin wrappers

qcom_scm-32 and qcom_scm-64 implementations are nearly identical, so
make qcom_scm_call and qcom_scm_call_atomic unique to each and the SCM
descriptor creation common to each. There are the following catches:
- __qcom_scm_is_call_available is still in each -32,-64 implementation
  as the argument is unique to each convention
- For some functions, only one implementation was provided in -32 or
  -64. The actual implementation was moved into qcom_scm.c
- io_writel and io_readl in -64 were non-atomic calls and in -32 they
  were. Atomic is the better option, so use it.

Tested-by: Brian Masney <[email protected]> # arm32
Tested-by: Stephan Gerhold <[email protected]>
Signed-off-by: Elliot Berman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bjorn Andersson <[email protected]>

Author: eberman-quic