libsframe: fixup comment and minor style issues

Also, use ATTRIBUTE_UNUSED consistently.

libsframe/
	* sframe.c (sframe_encoder_add_funcdesc): Fix function-level
	comment and use ATTRIBUTE_UNUSED consistently.
	(sframe_encoder_add_funcdesc_v2): Use ATTRIBUTE_UNUSED
	consistently.

libsframe/sframe.c

diff --git a/libsframe/sframe.c b/libsframe/sframe.c
index d482d58..659b39d 100644
--- a/libsframe/sframe.c
+++ b/libsframe/sframe.c
@@ -876,7 +876,7 @@
   return 0;
 }
 
-/* Decode the specified SFrame buffer CF_BUF of size CF_SIZE and return the
+/* Decode the specified SFrame buffer SF_BUF of size SF_SIZE and return the
    new SFrame decoder context.
 
    Sets ERRP for the caller if any error.  Frees up the allocated memory in
@@ -1639,7 +1639,7 @@
 			     int32_t start_addr,
 			     uint32_t func_size,
 			     unsigned char func_info,
-			     uint32_t num_fres __attribute__ ((unused)))
+			     uint32_t num_fres ATTRIBUTE_UNUSED)
 {
   sframe_header *ehp;
   sf_fde_tbl *fd_info;
@@ -1721,7 +1721,7 @@
 				uint32_t func_size,
 				unsigned char func_info,
 				uint8_t rep_block_size,
-				uint32_t num_fres __attribute__ ((unused)))
+				uint32_t num_fres ATTRIBUTE_UNUSED)
 {
   sf_fde_tbl *fd_info;
   int err;