mb/google/kahlee/nuwani: Create Nuwani variant
This commit creates a nuwani variant for Grunt. The initial settings
override the baseboard was copied from variant treeya.
BUG=b:
144890301
TEST=emerge-grunt coreboot
Signed-off-by: Peichao Wang <peichao.wang@bitland.corp-partner.google.com>
Change-Id: Id3a7fc890340e5a88ebc4b516dc2c0b085654999
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39316
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Mathew King <mathewk@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>