build: Bump gdbstub and gdbstub_arch

This commit also makes changes due to the breaking API changes from the
`gdbstub` crate [1].

[1] https://github.com/daniel5151/gdbstub/releases/tag/0.7.0

Fix: #5997

Signed-off-by: Bo Chen <chen.bo@intel.com>

vmm/src/gdb.rs

@@ -243,7 +243,7 @@ impl MultiThreadBase for GdbStub {
         start_addr: <Self::Arch as Arch>::Usize,
         data: &mut [u8],
         tid: Tid,
-    ) -> TargetResult<(), Self> {
+    ) -> TargetResult<usize, Self> {
         match self.vm_request(
             GdbRequestPayload::ReadMem(GuestAddress(start_addr), data.len()),
             tid_to_cpuid(tid),
@@ -252,7 +252,7 @@ impl MultiThreadBase for GdbStub {
                 for (dst, v) in data.iter_mut().zip(r.iter()) {
                     *dst = *v;
                 }
-                Ok(())
+                Ok(std::cmp::min(data.len(), r.len()))
             }
             Ok(s) => {
                 error!("Unexpected response for ReadMem: {:?}", s);