When given a relative path to the kernel git tree, update-kernel-headers.sh fails to execute the headers_install.sh script from the kernel sources. Fix it by turning the kernel directory into an absolute path. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>