ARM: dts: msm: Add GSI channels for SPI serial engines on SDM845

Add the DMA channel definitions for all SPI serial engines.
SPI controller will choose GSI DMA as the default data transfer method
and fall back to SW IO mode (FIFO mode) only if dma channel definitions
are removed from the device tree.

Change-Id: I76dbbf4045b42dc4020c1387ce8d302994eadc34
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>