build_kernel: generate kernel headers tarball
build_kernel: generate kernel headers tarball

This patch adds an option to generate the kernel headers tarball. It
can be used to build out-of-tree kernel modules. This patch sets it is
not default to avoid long build time and provides the --kernel-headers
option.

Change-Id: I55088068bda8c5da895850460d312ba656351539
Signed-off-by: Chanho Park <8ec285a53e21b773fd914e03c50e1b6431bc9aa8@samsung.com>

SamsungARTIK/build-artik