rb532: Fix initramfs kernel images

The generic lzma-loader uses vmlinux.lzma as an input to compress so we
need to provide a lzma compressed version of the initramfs kernel.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

target/linux/rb532/image/Makefile

@@ -28,7 +28,7 @@ define Image/Prepare
 	$(MAKE) -C $(GENERIC_PLATFORM_DIR)/image/lzma-loader $(LOADER_MAKEOPTS) clean compile
 ifeq ($(CONFIG_TARGET_ROOTFS_INITRAMFS),y)
 	$(STAGING_DIR_HOST)/bin/patch-cmdline $(KDIR)/vmlinux-initramfs '$(strip $(call Image/cmdline/yaffs2)) '
-	cat $(KDIR)/vmlinux-initramfs | $(STAGING_DIR_HOST)/bin/lzma e -si -so -eos -lc1 -lp2 -pb2 > $(KDIR)/vmlinux-initramfs.lzma
+	cat $(KDIR)/vmlinux-initramfs | $(STAGING_DIR_HOST)/bin/lzma e -si -so -eos -lc1 -lp2 -pb2 > $(KDIR)/vmlinux.lzma
 	$(MAKE) -C $(GENERIC_PLATFORM_DIR)/image/lzma-loader $(LOADER_MAKEOPTS) clean compile
 	$(CP) $(KDIR)/loader.elf $(KDIR)/loader-initramfs.elf
 endif