mmc: dw_mmc: Add support for SOCFPGA's platform specific implementation

Like the rockchip, Altera's SOCFPGA platform specific implementation of the
dw_mmc driver requires using the HOLD register for SD commands. This patch
renames dw_mci_rockchip_prepare_command to dw_mci_pltfm_prepare_command so
that SOCFPGA and Rockchip can use it.

Signed-off-by: Dinh Nguyen <[e-mail]>
Acked-by: Steffen Trumtrar <[e-mail]>
Tested-by: Steffen Trumtrar <[e-mail]>
Acked-by: Seungwon Jeon <[e-mail]>
Signed-off-by: Chris Ball <[e-mail]>

drivers/mmc/host/dw_mmc-pltfm.c

···
 #include "dw_mmc.h"
 #include "dw_mmc-pltfm.h"
 
-static void dw_mci_rockchip_prepare_command(struct dw_mci *host, u32 *cmdr)
+static void dw_mci_pltfm_prepare_command(struct dw_mci *host, u32 *cmdr)
 {
 	*cmdr |= SDMMC_CMD_USE_HOLD_REG;
 }
 
 static const struct dw_mci_drv_data rockchip_drv_data = {
-	.prepare_command	= dw_mci_rockchip_prepare_command,
+	.prepare_command	= dw_mci_pltfm_prepare_command,
+};
+
+static const struct dw_mci_drv_data socfpga_drv_data = {
+	.prepare_command	= dw_mci_pltfm_prepare_command,
 };
 
 int dw_mci_pltfm_register(struct platform_device *pdev,
···
 	{ .compatible = "snps,dw-mshc", },
 	{ .compatible = "rockchip,rk2928-dw-mshc",
 		.data = &rockchip_drv_data },
+	{ .compatible = "altr,socfpga-dw-mshc",
+		.data = &socfpga_drv_data },
 	{},
 };
 MODULE_DEVICE_TABLE(of, dw_mci_pltfm_match);