sysmocom-idu: Pick the right tune level

Depending on the upstream version (dora or not) we need to
use either core2 or core2-32. Use a python block expression
to pick this depending on the distro version.

conf/machine/sysmocom-idu.conf

@@ -17,7 +17,9 @@ MACHINE_FEATURES += "kernel26 x86 usbhost pci acpi"
 KERNEL_IMAGETYPE = "bzImage"
 
 IMAGE_FSTYPES = "ext4"
-DEFAULTTUNE="core2"
+
+# After dora core2 got renamed to core2-32
+DEFAULTTUNE="${@['core2-32','core2'][d.getVar('DISTRO_VERSION', True)[0:3] == '1.5']}"
 
 SERIAL_CONSOLE = "115200 ttyS0"
 MACHINE_CONSOLE = "console=ttyS0,115200n8"