util/cbfstool: Replace swab.h with commonlib/bsd/sysincludes.h

Instead of maintaining another set of byteswapping functions in
cbfstool, this change removes swab.h and replaces it with
bsd/sysincludes.h from commonlib. Callers have been updated to use
be32toh/be64toh/htobe32/htobe64 instead of ntohl/ntohll/htonl/htonll
respectively.

Change-Id: I54195865ab4042fcf83609fcf67ef8f33994d68e
Signed-off-by: Alex James <theracermaster@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60233
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Julius Werner <jwerner@chromium.org>

util/cbfstool/cbfs.h

@@ -54,7 +54,7 @@ static struct typedesc_t filetypes[] unused = {
 	{0, NULL}
 };
 
-#define CBFS_SUBHEADER(_p) ( (void *) ((((uint8_t *) (_p)) + ntohl((_p)->offset))) )
+#define CBFS_SUBHEADER(_p) ( (void *) ((((uint8_t *) (_p)) + be32toh((_p)->offset))) )
 
 static inline size_t cbfs_file_attr_hash_size(enum vb2_hash_algorithm algo)
 {