buildroot

linux: Add kernel compression selection.

This selection will ensure that the correct host tools
will be build used for the kernel compression method used.

[Maxime: Select the compression opts in the kernel config too ]

Signed-off-by: Sagaert Johan <sagaert.johan@proximus.be>
Signed-off-by: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>