patch 9.1.0472: Inconsistencies between functions for option flags

Problem:  Inconsistencies between functions for option flags.
Solution: Consistently use "unsigned int" as return type and rename
          get_bkc_value() to get_bkc_flags() (zeertzjq).

closes: #14925

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/bufwrite.c b/src/bufwrite.c
index bf79ad5..c9d9875 100644
--- a/src/bufwrite.c
+++ b/src/bufwrite.c
@@ -690,7 +690,7 @@
     int		    write_undo_file = FALSE;
     context_sha256_T sha_ctx;
 #endif
-    unsigned int    bkc = get_bkc_value(buf);
+    unsigned int    bkc = get_bkc_flags(buf);
     pos_T	    orig_start = buf->b_op_start;
     pos_T	    orig_end = buf->b_op_end;