env_nand.c: print error message and fail gracefully

env_nand.c would crash silently if a malloc() for the environment
buffers failed; make it print an error message and fail gracefully,
i. e. use the default environment then.

Signed-off-by: Wolfgang Denk <wd@denx.de>
Acked-by: John Rigby <jcrigby@gmail.com>

common/env_nand.c

@@ -298,6 +298,13 @@ void env_relocate_spec (void)
 	tmp_env1 = (env_t *) malloc(CONFIG_ENV_SIZE);
 	tmp_env2 = (env_t *) malloc(CONFIG_ENV_SIZE);
 
+	if ((tmp_env1 == NULL) || (tmp_env2 == NULL)) {
+		puts("Can't allocate buffers for environment\n");
+		free (tmp_env1);
+		free (tmp_env2);
+		return use_default();
+	}
+
 	if (readenv(CONFIG_ENV_OFFSET, (u_char *) tmp_env1))
 		puts("No Valid Environment Area Found\n");
 	if (readenv(CONFIG_ENV_OFFSET_REDUND, (u_char *) tmp_env2))