Documentation/sphinx: change pdflatex interaction mode to batchmode

Radically reduce the noise on stdout. The full build logs will still be
available under Documentatio/output/latex/*.log.

Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Tested-by: Markus Heiser <markus.heiser@darmarIT.de>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Documentation/Makefile.sphinx

@@ -11,7 +11,7 @@ SPHINX_CONF   = conf.py
 PAPER         =
 BUILDDIR      = $(obj)/output
 PDFLATEX      = xelatex
-LATEXOPTS     = -interaction=nonstopmode
+LATEXOPTS     = -interaction=batchmode
 
 # User-friendly check for sphinx-build
 HAVE_SPHINX := $(shell if which $(SPHINXBUILD) >/dev/null 2>&1; then echo 1; else echo 0; fi)