spi: spi-geni-qcom: Add support for DFS clk select

QUPv3 Serial Engines(SE) are sourced by DFS (dynamic frequency selector)
type root clocks. Add support to get the root frequency and DFS index
needed for a requested slave frequency.

Change-Id: I34d8ebdc38a0d04bbff2e0a02fd8b35cd211a20f
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>
1 file changed