imxtract: specify max gunzip size

Specify max gunzip size from config to override SYS_XIMG_LEN
default value wich is 0x800000. In case we have a large portion of FIT
image, for example gzipped kernel with decompressed size large than
0x800000 we should enlarge imxract area, otherwise extracting it will
fail.

It used to be a hardcoded define in cmd/ximg.c and we are moving it to
config.

Signed-off-by: Nikita Shubin <n.shubin@yadro.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/ximg.c b/cmd/ximg.c
index a50dd20..0e7eead 100644
--- a/cmd/ximg.c
+++ b/cmd/ximg.c
@@ -27,11 +27,6 @@
 #include <asm/cache.h>
 #include <asm/io.h>
 
-#ifndef CFG_SYS_XIMG_LEN
-/* use 8MByte as default max gunzip size */
-#define CFG_SYS_XIMG_LEN	0x800000
-#endif
-
 static int
 do_imgextract(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 {
@@ -52,7 +47,7 @@
 	size_t		fit_len;
 #endif
 #ifdef CONFIG_GZIP
-	uint		unc_len = CFG_SYS_XIMG_LEN;
+	uint		unc_len = CONFIG_SYS_XIMG_LEN;
 #endif
 	uint8_t		comp;