spi: bcm2835: Fix 3-wire mode if DMA is enabled [Linux 4.9.189]

This Linux kernel change "spi: bcm2835: Fix 3-wire mode if DMA is enabled" is included in the Linux 4.9.189 release. This change is authored by Lukas Wunner <lukas [at] wunner.de> on Wed Jul 3 12:29:31 2019 +0200. The commit for this change in Linux stable tree is a89b44e (patch) which is from upstream commit 8d8bef5. […]