sim: Allow access to the boot response

When the bootloader completes, it fills a response structure with
various information.  Move this into the BootGoResult and provide an
accessor for it.

Signed-off-by: David Brown <david.brown@linaro.org>
diff --git a/sim/mcuboot-sys/src/c.rs b/sim/mcuboot-sys/src/c.rs
index f8211d1..5c791b8 100644
--- a/sim/mcuboot-sys/src/c.rs
+++ b/sim/mcuboot-sys/src/c.rs
@@ -20,6 +20,8 @@
     Normal {
         result: i32,
         asserts: u8,
+
+        resp: api::BootRsp,
     },
 }
 
@@ -39,6 +41,7 @@
         matches!(self, BootGoResult::Normal {
             result: 0,
             asserts: 0,
+            ..
         })
     }
 
@@ -49,6 +52,14 @@
             _ => 0,
         }
     }
+
+    /// Retrieve the 'resp' field that is filled in.
+    pub fn resp(&self) -> Option<&api::BootRsp> {
+        match self {
+            BootGoResult::Normal { resp, .. } => Some(resp),
+            _ => None,
+        }
+    }
 }
 
 /// Invoke the bootloader on this flash device.
@@ -86,7 +97,7 @@
     if result == -0x13579 {
         BootGoResult::Stopped
     } else {
-        BootGoResult::Normal { result, asserts }
+        BootGoResult::Normal { result, asserts, resp: rsp }
     }
 }