[GIT PULL] dma mapping fix for 4.17-rc5

Hi Linus, one trivial dma-mapping regression fix for you. Note that this has NOT been in linux-next as I didn't want to disturb the branch in there which has the 4.18 material. I've asked Stephen to add the for-linus branch in addition to for-next so that this doesn't happen again. In addition

[GIT PULL] dma mapping fix for 4.17-rc5

Hi Linus, one trivial dma-mapping regression fix for you. Note that this has NOT been in linux-next as I didn't want to disturb the branch in there which has the 4.18 material. I've asked Stephen to add the for-linus branch in addition to for-next so that this doesn't happen again. In addition