mmc: zynq_sdhci: Add support for dynamic configuration

Add support for dynamic configuration which will takes care of
configuring the SD secure space configuration registers using firmware
APIs, performing SD reset assert and deassert.

High level sequence:
  - Check for the PM dynamic configuration support, if no error proceed
    with SD dynamic configurations(next steps) otherwise skip the dynamic
    configuration.
  - Put the SD Controller in reset.
  - Configure SD Fixed configurations.
  - Configure the SD Slot Type.
  - Configure the BASE_CLOCK.
  - Configure the 8-bit support.
  - Bring the SD Controller out of reset.

In the above steps, apart from the Fixed configurations, remaining all
configurations are dynamic and they will be read from devicetree.

And also remove hardcoded secure register writes, as dynamic sd config
support is added.

Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/030a3ec041ff3efebd574b4d2b477ad85f12cbce.1645626962.git.michal.simek@xilinx.com