mmc: sdhci: make max-frequency property in device tree work
mmc: sdhci: make max-frequency property in device tree work

Device tree provides option to specify the max freqency with property
"max-frequency" in dts and common parse function mmc_of_parse() will
parse it and use this value to set host->f_max to tell the MMC core
the maxinum frequency the host works.

However, current sdhci driver will finally overwrite this value with
host->max_clk regardless of the max-frequency property.

This patch makes sure not overwrite the max-frequency set from device
tree and do basic sanity check.

Signed-off-by: Dong Aisheng <2b078277ee35da55cb781a09fbe3a1f3f85cc310@freescale.com>
Reviewed-by: Johan Derycke <41cd252d2ce2073b6bc71c9090d0c2f9d89f4e47@barco.com>
Signed-off-by: Ulf Hansson <fe47b31f388f85ce6ddf64bf3a0cf6b46077d0e6@linaro.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs