image: fix bootm failure for FIT image

Commit b3dd64f5d537 "bootm: use genimg_get_kernel_addr()" introduced
a bug for booting FIT image. It's because calling fit_parse_config()
twice will give us wrong value in img_addr.

Add a new function genimg_get_kernel_addr_fit() whichl will always
return fit_uname_config and fit_uname_kernel for CONFIG_FIT.
genimg_get_kernel_addr() will ignore those to parameters.

Reported-by: York Sun <yorksun@freescale.com>
Signed-off-by: Bryan Wu <pengw@nvidia.com>
diff --git a/common/bootm.c b/common/bootm.c
index 76d811c..245c82a 100644
--- a/common/bootm.c
+++ b/common/bootm.c
@@ -725,13 +725,14 @@
 #endif
 	ulong		img_addr;
 	const void *buf;
-#if defined(CONFIG_FIT)
 	const char	*fit_uname_config = NULL;
 	const char	*fit_uname_kernel = NULL;
+#if defined(CONFIG_FIT)
 	int		os_noffset;
 #endif
 
-	img_addr = genimg_get_kernel_addr(argv[0]);
+	img_addr = genimg_get_kernel_addr_fit(argv[0], &fit_uname_config,
+					  &fit_uname_kernel);
 
 	bootstage_mark(BOOTSTAGE_ID_CHECK_MAGIC);
 
@@ -788,10 +789,6 @@
 #endif
 #if defined(CONFIG_FIT)
 	case IMAGE_FORMAT_FIT:
-		if (!fit_parse_conf(argv[0], load_addr, &img_addr,
-					&fit_uname_config))
-			fit_parse_subimage(argv[0], load_addr, &img_addr,
-					&fit_uname_kernel);
 		os_noffset = fit_image_load(images, img_addr,
 				&fit_uname_kernel, &fit_uname_config,
 				IH_ARCH_DEFAULT, IH_TYPE_KERNEL,