KVM: x86: Fix pointer mistmatch warning when patching RET0 static calls

Cast kvm_x86_ops.func to 'void *' when updating KVM static calls that are
conditionally patched to __static_call_return0().  clang complains about
using mismatching pointers in the ternary operator, which breaks the
build when compiling with CONFIG_KVM_WERROR=y.

  >> arch/x86/include/asm/kvm-x86-ops.h:82:1: warning: pointer type mismatch
  ('bool (*)(struct kvm_vcpu *)' and 'void *') [-Wpointer-type-mismatch]

Fixes: 5be2226f ("KVM: x86: allow defining return-0 static calls")
Reported-by: Like Xu <like.xu.linux@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: David Dunn <daviddunn@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Message-Id: <20220223162355.3174907-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -1548,8 +1548,8 @@ static inline void kvm_ops_static_call_update(void)
 	WARN_ON(!kvm_x86_ops.func); __KVM_X86_OP(func)
 #define KVM_X86_OP_OPTIONAL __KVM_X86_OP
 #define KVM_X86_OP_OPTIONAL_RET0(func) \
-	static_call_update(kvm_x86_##func, kvm_x86_ops.func ? : \
-			   (void *) __static_call_return0);
+	static_call_update(kvm_x86_##func, (void *)kvm_x86_ops.func ? : \
+					   (void *)__static_call_return0);
 #include <asm/kvm-x86-ops.h>
 #undef __KVM_X86_OP
 }