x86/jailhouse: Mark jailhouse_x2apic_available() as __init

.. as it is only called at early bootup stage.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: jailhouse-dev@googlegroups.com
Link: https://lkml.kernel.org/r/1561539289-29180-1-git-send-email-zhenzhong.duan@oracle.com

arch/x86/kernel/jailhouse.c

@@ -203,7 +203,7 @@ bool jailhouse_paravirt(void)
 	return jailhouse_cpuid_base() != 0;
 }
 
-static bool jailhouse_x2apic_available(void)
+static bool __init jailhouse_x2apic_available(void)
 {
 	/*
 	 * The x2APIC is only available if the root cell enabled it. Jailhouse