KVM: vmx: rename pi_init to avoid conflict with paride

allyesconfig results in:

ld: drivers/block/paride/paride.o: in function `pi_init':
(.text+0x1340): multiple definition of `pi_init'; arch/x86/kvm/vmx/posted_intr.o:posted_intr.c:(.init.text+0x0): first defined here
make: *** [Makefile:1164: vmlinux] Error 1

because commit:

commit 8888cdd0
Author: Xiaoyao Li <xiaoyao.li@intel.com>
Date:   Wed Sep 23 11:31:11 2020 -0700

    KVM: VMX: Extract posted interrupt support to separate files

added another pi_init(), though one already existed in the paride code.
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/posted_intr.c

@@ -222,7 +222,7 @@ void pi_wakeup_handler(void)
 	spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu));
 }
 
-void __init pi_init(int cpu)
+void __init pi_init_cpu(int cpu)
 {
 	INIT_LIST_HEAD(&per_cpu(blocked_vcpu_on_cpu, cpu));
 	spin_lock_init(&per_cpu(blocked_vcpu_on_cpu_lock, cpu));

arch/x86/kvm/vmx/posted_intr.h

@@ -91,7 +91,7 @@ void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu);
 int pi_pre_block(struct kvm_vcpu *vcpu);
 void pi_post_block(struct kvm_vcpu *vcpu);
 void pi_wakeup_handler(void);
-void __init pi_init(int cpu);
+void __init pi_init_cpu(int cpu);
 bool pi_has_pending_interrupt(struct kvm_vcpu *vcpu);
 int pi_update_irte(struct kvm *kvm, unsigned int host_irq, uint32_t guest_irq,
 		   bool set);

arch/x86/kvm/vmx/vmx.c

@@ -8004,7 +8004,7 @@ static int __init vmx_init(void)
 	for_each_possible_cpu(cpu) {
 		INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu));
 
-		pi_init(cpu);
+		pi_init_cpu(cpu);
 	}
 
 #ifdef CONFIG_KEXEC_CORE