kvm: remove unnecessary PageReserved check

The same check is already done in kvm_is_reserved_pfn.
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

virt/kvm/kvm_main.c

@@ -1855,8 +1855,7 @@ void kvm_set_pfn_dirty(kvm_pfn_t pfn)
 	if (!kvm_is_reserved_pfn(pfn)) {
 		struct page *page = pfn_to_page(pfn);
 
-		if (!PageReserved(page))
-			SetPageDirty(page);
+		SetPageDirty(page);
 	}
 }
 EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty);