x86/traps: Move cpu_init() out of trap_init()

cpu_init() doesn't particularly belong in trap_init().  This brings the BSP
more in line with the APs.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/setup.c

@@ -2024,6 +2024,8 @@ void asmlinkage __init noreturn __start_xen(void)
 
     trap_init();
 
+    cpu_init();
+
     rcu_init();
 
     early_time_init();

xen/arch/x86/traps.c

@@ -1938,8 +1938,6 @@ void __init trap_init(void)
             l1e_from_pfn(virt_to_mfn(boot_compat_gdt), __PAGE_HYPERVISOR_RW);
 
     percpu_traps_init();
-
-    cpu_init();
 }
 
 void asm_domain_crash_synchronous(unsigned long addr)