platform/x86/intel/uncore-freq: Use sysfs API to create attributes

Use of sysfs API is always preferable over using kobject calls to create
attributes. Remove usage of kobject_init_and_add() and use
sysfs_create_group(). To create relationship between sysfs attribute
and uncore instance use device_attribute*, which is defined per
uncore instance.

To create uniform locking for both read and write attributes take
lock in the sysfs callbacks, not in the actual functions where
the MSRs are read or updated.

No functional changes are expected.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20220204000306.2517447-3-srinivas.pandruvada@linux.intel.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>