ACPI: CPPC: Fix some kernel-doc comments

Add the description of @pcc_ss_id in pcc_data_alloc().
Add the description of @cpu_num in cppc_get_transition_latency().

clear the below warnings:
drivers/acpi/cppc_acpi.c:607: warning: Function parameter or member 'pcc_ss_id' not described in 'pcc_data_alloc'
drivers/acpi/cppc_acpi.c:1616: warning: Function parameter or member 'cpu_num' not described in 'cppc_get_transition_latency'

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=3983
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
[ rjw: Dropped redundant empty code lines, minor edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>