Android.mk: Tweak MESA_ENABLE_LLVM checks
Change the MESA_ENABLE_LLVM checks in Android.mk
files in order to get mesa3d to build w/ AOSP
using mmma.
This tries to re-create a change that was introduced
in the following merge in the AOSP branch:
69f2c0128d2b Merge branch 'aosp/upstream-18.0'
Acked-by: Tapani Pälli <tapani.palli@intel.com>
Acked-by: Mauro Rossi <issor.oruam@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4175>