Remove use of .INTERMEDIATE

make 3.81 has a bug where combining an up-to-date .INTERMEDIATE rule
with -j causes an infinite loop (http://savannah.gnu.org/bugs/?15919).
.INTERMEDIATE was only necessary to support multiple outputs while only
running a command once, remove .INTERMEDIATE by replacing
$(KATI_OUTPUTS) dependencies with $(KATI_BUILD_NINJA).  We can assume
that $(KATI_NINJA_SH) will be updated at the same time as
$(KATI_BUILD_NINJA), and not explicitly depend on it.

Also remove generateonly and fastincremental, which are no longer
necessary and were overcomplicating ninja.mk.  kati now always runs due
to FORCE, and ninja is run by a phony rule that depends on
$(KATI_BUILD_NINJA).

Bug: 25344116
Change-Id: I99d2713b1532ea11d83da9a11b1be26cfe13a5d2