ACPI: CPPC: Modify cppc_get_auto_sel_caps() to cppc_get_auto_sel()

ACPI: CPPC: Modify cppc_get_auto_sel_caps() to cppc_get_auto_sel()

Modify cppc_get_auto_sel_caps() to cppc_get_auto_sel(). Using a
cppc_perf_caps to carry the value is unnecessary.

Add a check to ensure the pointer 'enable' is not null.

Reviewed-by: Pierre Gondois <pierre.gondois@arm.com>
Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://patch.msgid.link/20250411093855.982491-8-zhenglifeng1@huawei.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>