platform/x86: amd: pmc: provide user message where s0ix is not supported

platform/x86: amd: pmc: provide user message where s0ix is not supported

Some platforms do not support hardware backed s0i3 transitions. When such
CPUs are detected, provide a warning message to the user.

Suggested-by: Sanket Goswami <Sanket.Goswami@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20230412111500.2602529-1-Shyam-sundar.S-k@amd.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>