mmc: zynqmp: Add HS200 modes support for ZynqMP

This patch adds HS200 suuport for ZynqMP and enables
the same for ZC1751 DC1 board which has eMMC on it.

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>