uboot-imx

mmc: sdhci: Add support for disabling clock

This patch adds support to disable clock if clk_disable
was set and then enable or set clock if the clock was changed
or clock was disabled when clock needs to be enabled.

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