First check in the function is if swsci() is supported. All the error
paths are easy to figure out the reason, so remove the extra debug
message: it's normal not to support swsci() e.g. in dgfx.

v2: Rather than special case dgfx, just remove the debug message
    (from Ville)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201027044618.719064-2-lucas.demarchi@intel.com