machine/*.conf: Set SPL_BINARY with weak assignment ?= in machine configs

Set SPL_BINARY with ?= instead of = to allow overwrite for this variable
without using forcevariable. When not using xilinx-bootbin to generate
the boot.bin, this variable should be set to '', to deploy spl boot.bin.

Signed-off-by: Jaewon Lee <jaewon.lee@xilinx.com>
Signed-off-by: Bhargava Sreekantappa Gayathri <bhargava.sreekantappa-gayathri@xilinx.com>
Signed-off-by: Manjukumar Matha <manjukumar.harthikote-matha@xilinx.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/meta-xilinx-bsp/conf/machine/picozed-zynq7.conf b/meta-xilinx-bsp/conf/machine/picozed-zynq7.conf
index 072d32a5..911bf90e 100644
--- a/meta-xilinx-bsp/conf/machine/picozed-zynq7.conf
+++ b/meta-xilinx-bsp/conf/machine/picozed-zynq7.conf
@@ -17,7 +17,7 @@ MACHINE_FEATURES = "ext2 vfat usbhost usbgadget"
 # u-boot configuration
 PREFERRED_PROVIDER_virtual/bootloader = "u-boot"
 UBOOT_MACHINE = "zynq_picozed_config"
-SPL_BINARY = "spl/boot.bin"
+SPL_BINARY ?= "spl/boot.bin"
 
 EXTRA_IMAGEDEPENDS += " \
                 u-boot-zynq-uenv \