Kernel 4.4.6+ on RaspberryPi support .dtbo files for overlays, instead of .dtb.
Add support for both variants of overlays ("-overlay.dtb" and ".dtbo")
Change which variant needs to be supported based on the kernel version
CAUTION: when called from IMAGE_CMD_rpi-sdimg, 'TMPDIR' is not set, causing 'STAGING_KERNEL_BUILDDIR' to not be expanded, causing get_kernelversion_file() to fail!
To avoid this problem, get_dts() and split_overlays() MUST be called with the kernel version parameter set, when called from IMAGE_CMD_rpi-sdimg!
Signed-off-by: Herve Jourdain <herve.jourdain@neuf.fr>
After '6392a63 rpi-base.inc: Use KERNEL_DEVICETREE by default' was
introduced, kernel versions < 3.18 might not be buildable. Since full
device tree support was introduced in 3.18 this change ensures that all
kernel < 3.18 will automatically disable device tree.
Signed-off-by: Petter Mabäcker <petter@technux.se>
