downstream iommu: deal w/ tlb on maps

Downstream kernel has this crazy MSM_IOMMU_TLBINVAL_ON_MAP option which
was missed when fwd porting downstream msm-iommu-v1 driver.  I can't
really imagine *why* you'd want something like that, it seems like an
incredibly bad idea.  But just define the config option in header to
make the various iommu map paths actually work.

Without this we'd see memory corruption and sometimes gpu hangs with the
gpu (surprisingly enough).

Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>