x86/itmt: Add debugfs file to show core priorities

Multiple drivers can report priorities to ITMT. To aid in debugging
any issues with the values reported by drivers introduce a debugfs
file to read out the values.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/20250609200518.3616080-14-superm1@kernel.org