Fix sandbox build on Ubuntu 10.04

gcc 4.4.3 (which is the default native compiler on x86-64 Ubuntu 10.04)
doesn't seem to like initializers for sub-fields of anonymous unions.
Solve this by replacing the initialization with an assignment. This
fixes:

lib/lz4_wrapper.c: In function ‘ulz4fn’:
lib/lz4_wrapper.c:97: error: unknown field ‘raw’ specified in initializer
Signed-off-by: NStephen Warren <swarren@wwwdotorg.org>
Reviewed-by: NTom Rini <trini@konsulko.com>
Acked-by: NSimon Glass <sjg@chromium.org>

lib/lz4_wrapper.c

@@ -94,7 +94,9 @@ int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn)
 	}
 
 	while (1) {
-		struct lz4_block_header b = { .raw = le32_to_cpu(*(u32 *)in) };
+		struct lz4_block_header b;
+
+		b.raw = le32_to_cpu(*(u32 *)in);
 		in += sizeof(struct lz4_block_header);
 
 		if (in - src + b.size > srcn) {