mmc: msm_sdcc: Enable SDC host->clk only after setting the rate.

For clocks that support rates which can be set (most clocks other
than _pclk AHB clocks), a rate must be set using clk_set_rate()
before the clock is enabled for the first time with clk_enable().
Subsequent calls to clk_enable() need not be preceded with the
clk_set_rate() calls unless we wish to change the clock rate that
is set previously.

SDC host->clk is currently enabled without setting the clock rate
even once. This patch fixes this, by ensuring that the clock rate
for this clock is first set before enabling the clock.

Signed-off-by: Murali Palnati <palnatim@codeaurora.org>
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Signed-off-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Chris Ball <cjb@laptop.org>