remove include/chromebook.sh import script (not needed)

i will be adding chromebooks, but not using this script,
which is why i never finished the script. i previously
had the plan to patch upstream coreboot, by importing
patches from mrchromebox, but that results in an extreme
number of patches. several hundred patches, in fact.

more efficient is to add multi-upstream support in
include/get.sh, for using different upstreams including
forks, on a given multi-tree project. i haven't done
this yet, but this is what will be done, and then
adding each chromebook will be a matter of importing
configs from mrchromebox alongside edk2 integration.

a script will still need to be written, for the initial
import, and imported chromebooks will be set release=n
until and when each target is fully tested.

Signed-off-by: Leah Rowe <leah@libreboot.org>

include/common.sh

@@ -8,12 +8,10 @@
 . "include/rom.sh"
 . "include/release.sh"
 . "include/get.sh"
-. "include/chromebook.sh"
 
 xbcommands=" \
 version \
 release \
 download \
 inject \
-prep_mr_import \
 "