x86/xen: make xen_pvmmu_arch_setup() static

Fix the following sparse warning:

arch/x86/xen/setup.c:998:12: warning: symbol 'xen_pvmmu_arch_setup' was not
declared. Should it be static?

Reported-by: Hulk Robot <[email protected]>
Signed-off-by: Jason Yan <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

Author: JasonYanHw

arch/x86/xen/setup.c

@@ -985,7 +985,7 @@ void xen_enable_syscall(void)
 #endif /* CONFIG_X86_64 */
 }
 
-void __init xen_pvmmu_arch_setup(void)
+static void __init xen_pvmmu_arch_setup(void)
 {
 	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
 	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);