mmc: sdhci: Distinguish between base clock and maximum peripheral frequency

The sdhci controller assumes that the base clock frequency is fully supported by
the peripheral and doesn't support hardware limitations. The Linux kernel
distinguishes between base clock (max_clk) of the host controller and maximum
frequency (f_max) of the card interface. Use the same differentiation and allow
the platform to constrain the peripheral interface.

Signed-off-by: Stefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com>
diff --git a/include/sdhci.h b/include/sdhci.h
index 7544b49..fdef7c4 100644
--- a/include/sdhci.h
+++ b/include/sdhci.h
@@ -244,6 +244,7 @@
 	unsigned int quirks;
 	unsigned int host_caps;
 	unsigned int version;
+	unsigned int max_clk;   /* Maximum Base Clock frequency */
 	unsigned int clk_mul;   /* Clock Multiplier value */
 	unsigned int clock;
 	struct mmc *mmc;
@@ -371,11 +372,11 @@
  *
  * @cfg:	Configuration structure to fill in (generally &plat->mmc)
  * @host:	SDHCI host structure
- * @max_clk:	Maximum supported clock speed in HZ (0 for default)
- * @min_clk:	Minimum supported clock speed in HZ (0 for default)
+ * @f_max:	Maximum supported clock frequency in HZ (0 for default)
+ * @f_min:	Minimum supported clock frequency in HZ (0 for default)
  */
 int sdhci_setup_cfg(struct mmc_config *cfg, struct sdhci_host *host,
-		    u32 max_clk, u32 min_clk);
+		    u32 f_max, u32 f_min);
 
 /**
  * sdhci_bind() - Set up a new MMC block device
@@ -401,11 +402,11 @@
  * This is used when you are not using CONFIG_BLK. Convert your driver over!
  *
  * @host:	SDHCI host structure
- * @max_clk:	Maximum supported clock speed in HZ (0 for default)
- * @min_clk:	Minimum supported clock speed in HZ (0 for default)
+ * @f_max:	Maximum supported clock frequency in HZ (0 for default)
+ * @f_min:	Minimum supported clock frequency in HZ (0 for default)
  * @return 0 if OK, -ve on error
  */
-int add_sdhci(struct sdhci_host *host, u32 max_clk, u32 min_clk);
+int add_sdhci(struct sdhci_host *host, u32 f_max, u32 f_min);
 #endif /* !CONFIG_BLK */
 
 #ifdef CONFIG_DM_MMC_OPS