mmc: zynq_sdhci: Add xilinx_pm_request() method to set tapdelays

mmc: zynq_sdhci: Add xilinx_pm_request() method to set tapdelays

Currently xilinx sdhci driver is using zynqmp_mmio_write() to set
tapdelay values and DLL resets. Continue to use this for SPL and mini
U-Boot where U-Boot will be executed at EL3 level.

Use firmware call xilinx_pm_request() using appropriate arguments to
set input/output tapdelays and also for DLL resets in regular flow(EL2).

Host driver should explicitly request DLL reset before ITAP (assert DLL)
and after OTAP (release DLL) to avoid issues in some cases. Also handle
error return where possible.

Signed-off-by: T Karthik Reddy <t.karthik.reddy@xilinx.com>
Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>