u-boot: Add nyan blaze chromebook configs

This adds U-Boot configuration for the HP Chromebook 14 G3, also known
as "nyan-blaze" but not in the U-Boot upstream defconfigs. Apparently
the "nyan-big" defconfig can also work for this version. It uses the
shared tree for the "nyan" baseboard. The config is almost the same as
upstream defconfig, but with REMAKE_ELF and POSITION_INDEPENDENT
enabled.

Untested since I don't have the nyan blaze chromebook.

Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>

resources/u-boot/nyan_blaze/board.cfg

+ubtree="veyron"
+arch="ARMv7"