[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/tools/mkimage.c b/tools/mkimage.c
index 8ced970..5119bc7 100644
--- a/tools/mkimage.c
+++ b/tools/mkimage.c
@@ -361,7 +361,7 @@
 						cmdname, file, strerror(errno));
 					exit (EXIT_FAILURE);
 				}
-				size = cpu_to_image (sbuf.st_size);
+				size = cpu_to_uimage (sbuf.st_size);
 			} else {
 				size = 0;
 			}
@@ -604,7 +604,7 @@
 		pos = image_get_header_size () + ptrs * sizeof(long);
 		printf ("Contents:\n");
 		for (i=0; len_ptr[i]; ++i) {
-			size = image_to_cpu (len_ptr[i]);
+			size = uimage_to_cpu (len_ptr[i]);
 
 			printf ("   Image %d: %8d Bytes = %4d kB = %d MB\n",
 				i, size, size>>10, size>>20);