mmc: sdhci: Update sdhci_send_command() to handle HS200

This patch updates sdhci_send_command() to handle MMC
HS200 tuning command.

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