plat(juno): use generic image fetching functions

Some generic functions have been provided for fetching prebuilt images -
use these for Juno runs.

Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
Change-Id: I77c1a0e3336ecdbbdba88078b8ee6e03dc760b0f
diff --git a/run_config/juno-linux.reboot+aarch32 b/run_config/juno-linux.reboot+aarch32
index 1c1614b..be30e2e 100644
--- a/run_config/juno-linux.reboot+aarch32
+++ b/run_config/juno-linux.reboot+aarch32
@@ -6,8 +6,9 @@
 #
 
 post_tf_build() {
-	get_scp_bl2_bin
-	get_uboot32_bin
+	url="${scp_bl2_url}" filename="scp_bl2.bin" fetch_and_archive
+	url="${uboot32_fip_url}" image="nt-fw.bin" output_name="uboot.bin" \
+	 get_boot_image_from_fip
 
 	# Building FIP for this config requries a BL32 built in AArch32, but
 	# we'll only build that later. An appropriate BL32 image must be updated