patch 8.0.1042: without the syntax feature highlighting doesn't work

Problem:    Without the syntax feature highlighting doesn't work.
Solution:   Always use unsigned short to store attributes.
diff --git a/src/vim.h b/src/vim.h
index 77081e2..93dc951 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -435,13 +435,8 @@
  * The characters and attributes cached for the screen.
  */
 typedef char_u schar_T;
-#ifdef FEAT_SYN_HL
 typedef unsigned short sattr_T;
-# define MAX_TYPENR 65535
-#else
-typedef unsigned char sattr_T;
-# define MAX_TYPENR 255
-#endif
+#define MAX_TYPENR 65535
 
 /*
  * The u8char_T can hold one decoded UTF-8 character.