patch 8.2.0616: build error when disabling the diff feature

Problem:    Build error when disabling the diff feature.
Solution:   Move parenthesis outside of #ifdef. (Tom Ryder)
diff --git a/src/drawline.c b/src/drawline.c
index 1544dae..8de307a 100644
--- a/src/drawline.c
+++ b/src/drawline.c
@@ -3095,9 +3095,9 @@
 #ifdef FEAT_SYN_HL
 	    if (!(cul_screenline
 # ifdef FEAT_DIFF
-			&& diff_hlf == (hlf_T)0)
+			&& diff_hlf == (hlf_T)0
 # endif
-		    )
+		    ))
 		saved_char_attr = char_attr;
 	    else
 #endif