aarch64 haskell: check cap type in checkVSpaceRoot

Correctly check the type of the table the PageTableCap points to in
checkVSpaceRoot (must be a VSRootPT, not NormalPT).

Signed-off-by: Gerwin Klein <gerwin.klein@proofcraft.systems>

spec/haskell/src/SEL4/Kernel/VSpace/AARCH64.hs

@@ -470,6 +470,7 @@ checkVSpaceRoot :: Capability  -> Int -> KernelF SyscallError (PPtr PTE, ASID)
 checkVSpaceRoot vspaceCap argNo =
     case vspaceCap of
         ArchObjectCap (PageTableCap {
+                capPTType = VSRootPT_T,
                 capPTMappedAddress = Just (asid, _),
                 capPTBasePtr = vspace })
             -> return (vspace, asid)