Fix silly gcc warning.

Explicitly specify the underlying type of LinkerPatch::Type
as uint8_t because gcc would select a bigger type and then
complain that
    'art::LinkerPatch::patch_type_' is too small to hold all
    values of 'enum class art::LinkerPatch::Type'
which is really ridiculous given that the enum contains only
a handful enumerators with default (small) values.

Change-Id: I4c4b21cde62e56b62488bae99d3690d900c3c29e
diff --git a/compiler/compiled_method.h b/compiler/compiled_method.h
index b5c99e8..70161eb 100644
--- a/compiler/compiled_method.h
+++ b/compiler/compiled_method.h
@@ -161,7 +161,14 @@
 
 class LinkerPatch {
  public:
-  enum class Type {
+  // Note: We explicitly specify the underlying type of the enum because GCC
+  // would otherwise select a bigger underlying type and then complain that
+  //     'art::LinkerPatch::patch_type_' is too small to hold all
+  //     values of 'enum class art::LinkerPatch::Type'
+  // which is ridiculous given we have only a handful of values here. If we
+  // choose to squeeze the Type into fewer than 8 bits, we'll have to declare
+  // patch_type_ as an uintN_t and do explicit static_cast<>s.
+  enum class Type : uint8_t {
     kRecordPosition,   // Just record patch position for patchoat.
     kMethod,
     kCall,