ARM: KVM: vgic: decouple alignment restriction from page size

The virtual GIC is supposed to be 4kB aligned. On a 64kB page
system, comparing the alignment to PAGE_SIZE is wrong.

Use SZ_4K instead.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/arch/arm/kvm/vgic.c b/arch/arm/kvm/vgic.c
index c9a1731..161d5c1 100644
--- a/arch/arm/kvm/vgic.c
+++ b/arch/arm/kvm/vgic.c
@@ -1484,7 +1484,7 @@
 	if (addr & ~KVM_PHYS_MASK)
 		return -E2BIG;
 
-	if (addr & ~PAGE_MASK)
+	if (addr & (SZ_4K - 1))
 		return -EINVAL;
 
 	mutex_lock(&kvm->lock);