[source] bcm53xx: Fix SmartRG SR400AC initramfs image

[LEDE Commits]

florian pushed a commit to source.git, branch master:
https://git.lede-project.org/7f0a32e21ca9edaa5607b98724e1eca05c8c50ba

commit 7f0a32e21ca9edaa5607b98724e1eca05c8c50ba
Author: Florian Fainelli <f.fainelli at gmail.com>
AuthorDate: Mon Oct 9 20:50:27 2017 -0700

    bcm53xx: Fix SmartRG SR400AC initramfs image
    
    The SmartRG SR400AC CFE does not accept a TRX image, just a normal
    binary image.
    
    Signed-off-by: Florian Fainelli <f.fainelli at gmail.com>
---
 target/linux/bcm53xx/image/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/target/linux/bcm53xx/image/Makefile b/target/linux/bcm53xx/image/Makefile
index 0d20c16..e4dca0c 100644
--- a/target/linux/bcm53xx/image/Makefile
+++ b/target/linux/bcm53xx/image/Makefile
@@ -307,6 +307,8 @@ define Device/smartrg-sr400ac
   DEVICE_PACKAGES := $(BRCMFMAC_43602A1) $(USB3_PACKAGES)
   IMAGES := trx
   IMAGE/trx := append-rootfs | trx-serial
+  KERNEL_INITRAMFS_SUFFIX := .bin
+  KERNEL_INITRAMFS := kernel-bin | append-dtb | lzma-d16
 endef
 TARGET_DEVICES += smartrg-sr400ac