The I.MX SDHCI driver assumes that the frequency of the 'per' clock
can be obtained even on disabled clocks, which is not always the case.

According to 'clk_get_rate' documentation, it is only valid
once the clock source has been enabled.
Signed-off-by: Ciprian Costea <ciprianmarian.costea@oss.nxp.com>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20240708121018.246476-3-ciprianmarian.costea@oss.nxp.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>