Documentation: Add make rule for sphinx-autobuild

Add livesphinx to start sphinx-autobuild

Change-Id: I9eb3217e758c2c882c759fa7ae75a39aaf1a0358
Signed-off-by: Tom Hiller <thrilleratplay@gmail.com>
Reviewed-on: https://review.coreboot.org/28210
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2 files changed