cpu/cpu.h: Remove unused functions prototypes

These were dropped with LEGACY_SMP_INIT.

Change-Id: Iecaf9ba3d31d22311557b885b31e98a0edd74d96
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69503
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Elyes Haouas <ehaouas@noos.fr>

src/include/cpu/cpu.h

@@ -13,8 +13,6 @@ uintptr_t cpu_get_lapic_addr(void);
 /* Function to keep track of cpu default apic_id */
 void cpu_add_map_entry(unsigned int index);
 struct bus;
-void initialize_cpus(struct bus *cpu_bus);
-asmlinkage void secondary_cpu_init(unsigned int cpu_index);
 int cpu_phys_address_size(void);
 
 #if ENV_RAMSTAGE