This adds an initial dts for the Dragonboard 845. Supported
functionality includes Debug UART, UFS, USB-C (peripheral), USB-A
(host), microSD-card and Bluetooth.

Initializing the SMMU is clearing the mapping used for the splash screen
framebuffer, which causes the board to reboot. This can be worked around
using:

  fastboot oem select-display-panel none
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Tested-by: Vinod Koul <vkoul@kernel.org>
Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>