fix(core): fix polkadot transfer amount decode issue (#568)

Author: somebodyLi

core/src/apps/polkadot/codec/types.py

@@ -21,7 +21,7 @@ def process_compact_bytes(self):
         elif byte_mod == 2:
             self.compact_length = 4
         else:
-            self.compact_length = int(5 + (compact_byte[0] - 3) / 4)
+            self.compact_length = int(5 + (compact_byte[0] - 3) >> 2)
 
         if self.compact_length == 1:
             self.compact_bytes = compact_byte
@@ -37,7 +37,7 @@ def process_compact_bytes(self):
     def process(self):
         self.process_compact_bytes()
         if self.compact_length <= 4:
-            return int(int.from_bytes(self.compact_bytes, "little") / 4)
+            return int(int.from_bytes(self.compact_bytes, "little") >> 2)
         else:
             return int.from_bytes(self.compact_bytes, "little")