soc/intel/xeon_sp: Rename cpx_generate_p_state_entries()

Prepare for common ACPI. Rename cpx_generated_p_state_entries()
to the common soc_power_states_generation() function. Add
empty soc_power_states_generation() to skx.

Change-Id: Ib7e8dfd2bb602f3e6ccdb5b221bc65236f66a875
Signed-off-by: Marc Jones <marcjones@sysproconsulting.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46598
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/src/soc/intel/xeon_sp/skx/soc_acpi.c b/src/soc/intel/xeon_sp/skx/soc_acpi.c
index 7462d72..df2550c 100644
--- a/src/soc/intel/xeon_sp/skx/soc_acpi.c
+++ b/src/soc/intel/xeon_sp/skx/soc_acpi.c
@@ -171,6 +171,10 @@
 	acpigen_pop_len();
 }
 
+void soc_power_states_generation(int core, int cores_per_package)
+{
+}
+
 unsigned long xeonsp_acpi_create_madt_lapics(unsigned long current)
 {
 	struct device *cpu;