hypervisor: tdx: do not use u64 to represent pointers

Also drop support for building the TDX code for 32-bit targets.  All
CPUs with TDX support are 64-bit so supporting 32-bit targets is not
needed.

Signed-off-by: Demi Marie Obenour <demiobenour@gmail.com>

vmm/src/vm.rs

@@ -2251,9 +2251,9 @@ impl Vm {
         for section in sections {
             self.vm
                 .tdx_init_memory_region(
-                    mem.get_host_address(GuestAddress(section.address)).unwrap() as u64,
+                    mem.get_host_address(GuestAddress(section.address)).unwrap(),
                     section.address,
-                    section.size,
+                    section.size.try_into().unwrap(),
                     /* TDVF_SECTION_ATTRIBUTES_EXTENDMR */
                     section.attributes == 1,
                 )