mmc: sdhci-brcmstb: use clk_get_rate(base_clk) in PM resume

Use clk_get_rate for base_clk on resume before setting new rate.
This change ensures that the clock api returns current rate
and sets the clock to the desired rate and honors CLK_GET_NO_CACHE
attribute used by clock api.

Fixes: 97904a59 (mmc: sdhci-brcmstb: Add ability to increase max clock rate for 72116b0)
Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220714174132.18541-1-kdasu.kdev@gmail.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>