spi-geni-qcom: Add new interfaces and utilise them

Merge series from Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>:

A "known issue" during implementation of SE DMA for spi geni driver was
that it does DMA map/unmap internally instead of in spi framework.
Current patches remove this hiccup and also clean up code a bit.

Testing revealed no regressions and results with 1000 iterations of
reading from EC showed no loss of performance.
Results
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Before - Iteration 999, min=5.10, max=5.17, avg=5.14, ints=25129
After  - Iteration 999, min=5.10, max=5.20, avg=5.15, ints=25153