[new uImage] Update naming convention for bootm/uImage related code

This patch introduces the following prefix convention for the
image format handling and bootm related code:

genimg_		- dual format shared code
image_		- legacy uImage format specific code
fit_		- new uImage format specific code
boot_		- booting process related code

Related routines are renamed and a few pieces of code are moved around and
re-grouped.

Signed-off-by: Marian Balakowicz <m8@semihalf.com>
diff --git a/common/cmd_autoscript.c b/common/cmd_autoscript.c
index f9ab1d9..60ffc7d 100644
--- a/common/cmd_autoscript.c
+++ b/common/cmd_autoscript.c
@@ -61,7 +61,7 @@
 
 	verify = getenv_verify ();
 
-	switch (gen_image_get_format ((void *)addr)) {
+	switch (genimg_get_format ((void *)addr)) {
 	case IMAGE_FORMAT_LEGACY:
 		hdr = (image_header_t *)addr;
 
@@ -90,7 +90,7 @@
 		/* get length of script */
 		data = (ulong *)image_get_data (hdr);
 
-		if ((len = image_to_cpu (*data)) == 0) {
+		if ((len = uimage_to_cpu (*data)) == 0) {
 			puts ("Empty Script\n");
 			return 1;
 		}