CDImage: Add helper for checking for SBI

src/common/cd_image_chd.cpp

@@ -49,6 +49,7 @@ public:
   bool Open(const char* filename);
 
   bool ReadSubChannelQ(SubChannelQ* subq) override;
+  bool HasNonStandardSubchannel() const override;
 
 protected:
   bool ReadSectorFromIndex(void* buffer, const Index& index, LBA lba_in_index) override;
@@ -262,6 +263,11 @@ bool CDImageCHD::ReadSubChannelQ(SubChannelQ* subq)
   return CDImage::ReadSubChannelQ(subq);
 }
 
+bool CDImageCHD::HasNonStandardSubchannel() const
+{
+  return (m_sbi.GetReplacementSectorCount() > 0);
+}
+
 // There's probably a more efficient way of doing this with vectorization...
 ALWAYS_INLINE static void CopyAndSwap(void* dst_ptr, const u8* src_ptr, u32 data_size)
 {