buildroot

configs/spns_axs*_defconfig: update linux and u-bootversion

With this commit we update axs10x defconfigs with the following changes:

 - rename "snps_axs101_defconfig" and "snps_axs103_defconfig" to
   "snps_arc700_axs101_defconfig" and "snps_archs38_axs103_defconfig",
   to reflect the ARC core being used
 - bump linux kernel version to 4.10.8
 - set up host linux headers to 4.10
 - bump u-boot version to 2017.01

Signed-off-by: Vlad Zakharov <vzakhar@synopsys.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>