km/scripts: replace hardcoded uImage

Replace uImage with ${uimage}.
If uimage is not set, default it to uImage.

Signed-off-by: Andreas Huber <andreas.huber@keymile.com>
Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
diff --git a/board/keymile/scripts/ramfs-common.txt b/board/keymile/scripts/ramfs-common.txt
index c1b45ab..8a8d287 100644
--- a/board/keymile/scripts/ramfs-common.txt
+++ b/board/keymile/scripts/ramfs-common.txt
@@ -4,8 +4,9 @@
 bootcmd=run ${subbootcmds}
 subbootcmds=tftpfdt tftpkernel setrootfsaddr tftpramfs flashargs add_default addpanic addramfs boot
 nfsargs=setenv bootargs root=/dev/nfs rw nfsroot=${serverip}:${rootpath}
-configure=km_setboardid && saveenv && reset
+configure=run set_uimage; km_setboardid && saveenv && reset
 rootfsfile=${hostname}/rootfsImage
 setrootfsaddr=setexpr value ${pnvramaddr} - ${rootfssize} && setenv rootfsaddr 0x${value}
-tftpkernel=tftpboot ${load_addr_r} ${hostname}/uImage
+tftpkernel=tftpboot ${load_addr_r} ${hostname}/${uimage}
 tftpramfs=tftpboot ${rootfsaddr} ${hostname}/rootfsImage
+set_uimage=printenv uimage || setenv uimage uImage