Makefile: Revise 'doc' build target.

Simplify doc build process, eliminate duplicated output, and archive
into bundle directly.

This also changed doc file type from tar.bz2 to zip, which is easier for
partner to access.

BUG=chromium:577601
TEST=make doc; make bundle

Change-Id: Id95c93f295fe336fbbc7a4c74b2b1e568471de9a
Reviewed-on: https://chromium-review.googlesource.com/393488
Commit-Ready: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Wei-Han Chen <stimim@chromium.org>
1 file changed