ODROID: scripts: change kernel URL

This patch is to change default kernel repository to tobetter's kernel
repository from Linaro's Ci kernel repository.

Signed-off-by: Dongjin Kim <tobetter@gmail.com>
ODROID: add ODROID-X v3.7 kernel based configuration

Signed-off-by: Dongjin Kim <tobetter@gmail.com>
ODROID: add ODROID-X v3.8 kernel based configuration

Signed-off-by: Dongjin Kim <tobetter@gmail.com>