platform/x86: amd-pmc: Move SMU logging setup out of init

SMU logging is setup when the device is probed currently.

In analyzing boot performance it was observed that amd_pmc_probe is
taking ~116800us on startup on an OEM platform.  This is longer than
expected, and is caused by enabling SMU logging at startup.

As the SMU logging is only needed for debugging, initialize it only upon
use.  This decreases the time for amd_pmc_probe to ~28800us.

Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20220411143820.13971-1-mario.limonciello@amd.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>