u-boot-xlnx-scr: Add PRE_BOOTENV variable for boot cmd files

Based on github Pull Request #34. While that pull request is no longer
valid with other changes, the actual bug still exists.

Originally reported by Felix S(ubfx).

Signed-off-by: Sandeep Gundlupet Raju <[email protected]>

Author: grsandeep85

meta-xilinx-core/recipes-bsp/u-boot/u-boot-xlnx-scr/boot.cmd.qspi.versal

@@ -1 +1,3 @@
+@@PRE_BOOTENV@@
+
 @@KERNEL_BOOTCMD@@ @@KERNEL_LOAD_ADDRESS@@ @@RAMDISK_IMAGE_ADDRESS@@ @@DEVICETREE_ADDRESS@@

meta-xilinx-core/recipes-bsp/u-boot/u-boot-xlnx-scr/boot.cmd.sd.versal

@@ -1,3 +1,5 @@
+@@PRE_BOOTENV@@
+
 setenv sdbootdev @@SDBOOTDEV@@
 setenv bootargs $bootargs root=/dev/mmcblk${sdbootdev}p2 rw rootwait earlycon clk_ignore_unused
 fatload mmc $sdbootdev @@DEVICETREE_ADDRESS@@ @@DEVICE_TREE_NAME@@

meta-xilinx-core/recipes-bsp/u-boot/u-boot-xlnx-scr/boot.cmd.sd.zynq

@@ -1,3 +1,5 @@
+@@PRE_BOOTENV@@
+
 if test -n "@@BITSTREAM@@"; then
    fatload mmc $sdbootdev @@BITSTREAM_LOAD_ADDRESS@@ @@BITSTREAM_IMAGE@@ && fpga @@BITSTREAM_LOAD_TYPE@@ 0 @@BITSTREAM_LOAD_ADDRESS@@ ${filesize}
 fi

meta-xilinx-core/recipes-bsp/u-boot/u-boot-xlnx-scr/boot.cmd.sd.zynqmp

@@ -1,3 +1,5 @@
+@@PRE_BOOTENV@@
+
 setenv sdbootdev @@SDBOOTDEV@@
 setenv bootargs $bootargs root=/dev/mmcblk${sdbootdev}p2 rw rootwait earlycon clk_ignore_unused
 if test -n "@@BITSTREAM@@"; then