arch/x86/kvm/mmu.c: work around gcc-4.4.4 bug

Fix this compile issue with gcc-4.4.4:

   arch/x86/kvm/mmu.c: In function 'kvm_mmu_pte_write':
   arch/x86/kvm/mmu.c:4256: error: unknown field 'cr0_wp' specified in initializer
   arch/x86/kvm/mmu.c:4257: error: unknown field 'cr4_pae' specified in initializer
   arch/x86/kvm/mmu.c:4257: warning: excess elements in union initializer
   ...

gcc-4.4.4 (at least) has issues when using anonymous unions in
initializers.

Fixes: edc90b7d ("KVM: MMU: fix SMAP virtualization")
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/kvm/mmu.c

@@ -4215,13 +4215,13 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 	u64 entry, gentry, *spte;
 	int npte;
 	bool remote_flush, local_flush, zap_page;
-	union kvm_mmu_page_role mask = (union kvm_mmu_page_role) {
-		.cr0_wp = 1,
-		.cr4_pae = 1,
-		.nxe = 1,
-		.smep_andnot_wp = 1,
-		.smap_andnot_wp = 1,
-	};
+	union kvm_mmu_page_role mask = { };
+
+	mask.cr0_wp = 1;
+	mask.cr4_pae = 1;
+	mask.nxe = 1;
+	mask.smep_andnot_wp = 1;
+	mask.smap_andnot_wp = 1;
 
 	/*
 	 * If we don't have indirect shadow pages, it means no page is