cmd: Add missing check for CONFIG_SYS_LONGHELP

Two commands are missing this check, so compilation fails when building
without CONFIG_CMDLINE. Add it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/bloblist.c b/cmd/bloblist.c
index 97b5734..21e7ff6 100644
--- a/cmd/bloblist.c
+++ b/cmd/bloblist.c
@@ -29,9 +29,11 @@
 	return 0;
 }
 
+#ifdef CONFIG_SYS_LONGHELP
 static char bloblist_help_text[] =
 	"info   - show information about the bloblist\n"
 	"bloblist list   - list blobs in the bloblist";
+#endif
 
 U_BOOT_CMD_WITH_SUBCMDS(bloblist, "Bloblists", bloblist_help_text,
 	U_BOOT_SUBCMD_MKENT(info, 1, 1, do_bloblist_info),