Don't log error for try_from failure for Register

This was caused by a bug within core which shouldn't be sending
temporary registers to the architecture. There's nothing we can do about
this and the guidance is to not print the error message.

Fixes #2

src/architecture.rs

@@ -364,10 +364,7 @@ impl Architecture for Msp430 {
     fn register_from_id(&self, id: u32) -> Option<Self::Register> {
         match id.try_into() {
             Ok(register) => Some(register),
-            Err(_) => {
-                error!("invalid register id {}", id);
-                None
-            }
+            Err(_) => None,
         }
     }
 

src/register.rs

@@ -27,6 +27,10 @@ impl TryFrom<u32> for Register {
     type Error = ();
 
     fn try_from(id: u32) -> Result<Self, Self::Error> {
+        // TODO: we should return separate errors if the id is between 0x7fff_ffff and 0xffff_ffff
+        // vs outside of that range. Temporary registers have have the high bit set which we
+        // shouldn't get, unless there is a bug in core. An id that isn't within that range but we
+        // don't handle is a bug in the architecture.
         match id {
             0 => Ok(Self::Pc),
             1 => Ok(Self::Sp),