mmc: sdhci: Make sdhci_set_clock() non static

The am654_sdhci driver needs to switch the clock off
before disabling its phy dll and needs to re-enable
the clock before enabling the phy again.

Therefore, make the sdhci_set_clock() function accessible
in the am654_sdhci driver.

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

include/sdhci.h

@@ -470,6 +470,7 @@ int add_sdhci(struct sdhci_host *host, u32 f_max, u32 f_min);
 #ifdef CONFIG_DM_MMC
 /* Export the operations to drivers */
 int sdhci_probe(struct udevice *dev);
+int sdhci_set_clock(struct mmc *mmc, unsigned int clock);
 extern const struct dm_mmc_ops sdhci_ops;
 #else
 #endif