gzip/zlib: make features optional

If you really want to slim down U-Boot and you would rather use a higher
compression scheme (like LZMA), it'd be nice to disable gzip/zlib since
these code bases take up a significant amount of space.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c
index f28e88f..23ab0c4 100644
--- a/common/cmd_bootm.c
+++ b/common/cmd_bootm.c
@@ -352,6 +352,7 @@
 		*load_end = load + image_len;
 		puts("OK\n");
 		break;
+#ifdef CONFIG_GZIP
 	case IH_COMP_GZIP:
 		printf ("   Uncompressing %s ... ", type_name);
 		if (gunzip ((void *)load, unc_len,
@@ -365,6 +366,7 @@
 
 		*load_end = load + image_len;
 		break;
+#endif /* CONFIG_GZIP */
 #ifdef CONFIG_BZIP2
 	case IH_COMP_BZIP2:
 		printf ("   Uncompressing %s ... ", type_name);