acpi_spmc(4): Factor out printing DSM call error, delineate function

[olce]

Summary

Introduce failed_to_call_dsm(), which prepends "function" before the
function index for better clarity. For now, it prints the function
number, as before, but will soon print a human-readable name.

[olce]

• Take the softc instead of the device.
• Remove passing the caller's name (does not give much more information, since apart from retrieving the constraints, all other calls are through the same function; and a later revision prints the DSM function's name, which is much more meaningful).

[olce]

Impacts of change in D56803, no real change.