cbfstool: Clean up code

cbfstool has diverged between coreboot upstream and the chromium tree.
Bring in some of the chromium changes, in particular the useful remainders
of cbf37fe (https://chromium-review.googlesource.com/176710)

- fix coding style
- mark unused variables explicitly unused
- remove some dead code

Change-Id: I354aaede8ce425ebe99d4c60c232feea62bf8a11
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/8577
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

util/cbfstool/cbfstool.c

@@ -118,7 +118,8 @@ static int cbfs_add_component(const char *cbfs_name,
 			      const char *name,
 			      uint32_t type,
 			      uint32_t offset,
-			      convert_buffer_t convert) {
+			      convert_buffer_t convert)
+{
 	struct cbfs_image image;
 	struct buffer buffer;
 
@@ -194,7 +195,9 @@ static int cbfstool_convert_mkstage(struct buffer *buffer, uint32_t *offset)
 	return 0;
 }
 
-static int cbfstool_convert_mkpayload(struct buffer *buffer, uint32_t *offset) {
+static int cbfstool_convert_mkpayload(struct buffer *buffer,
+						unused uint32_t *offset)
+{
 	struct buffer output;
 	int ret;
 	/* per default, try and see if payload is an ELF binary */
@@ -222,7 +225,8 @@ static int cbfstool_convert_mkpayload(struct buffer *buffer, uint32_t *offset) {
 }
 
 static int cbfstool_convert_mkflatpayload(struct buffer *buffer,
-					  uint32_t *offset) {
+					  unused uint32_t *offset)
+{
 	struct buffer output;
 	if (parse_flat_binary_to_payload(buffer, &output,
 					 param.loadaddress,