spi: spi-cadence-quadspi: add runtime pm support

spi: spi-cadence-quadspi: add runtime pm support

Add runtime pm support to cadence-qspi driver, this allows the driver to
suspend whenever it's is not actively being used thus reducing active
power consumed by the system.

Also, with the use of devm_pm_runtime_enable we no longer need the
fallback probe_pm_failed that used to pm_runtime_disable

Co-developed-by: Apurva Nandan <a-nandan@ti.com>
Signed-off-by: Apurva Nandan <a-nandan@ti.com>
Signed-off-by: Dhruva Gole <d-gole@ti.com>
Link: https://lore.kernel.org/r/20230829062706.786637-1-d-gole@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>