spi: spi-geni-qcom: Remove per transaction dmaengine pause and resume

Don't make a call to pause and resume the DMA channels as these calls are
expensive and can add to transaction times and these calls aren't needed
for the transfers to succeed.

Change-Id: I63aff4c8104e4a9ab63fbf2b5275db7462b5c886
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>