mmc: rtsx: clarify DDR timing mode between SD-UHS and eMMC

Added MMC_DDR52 as eMMC's DDR mode is distinguished from SD-UHS.

CC: Wei WANG <wei_wang@realsil.com.cn>
CC: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>

drivers/mmc/host/rtsx_pci_sdmmc.c

@@ -1075,6 +1075,7 @@ static int sd_set_timing(struct realtek_pci_sdmmc *host, unsigned char timing)
 		rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, CLK_CTL, CLK_LOW_FREQ, 0);
 		break;
 
+	case MMC_TIMING_MMC_DDR52:
 	case MMC_TIMING_UHS_DDR50:
 		rtsx_pci_add_cmd(pcr, WRITE_REG_CMD, SD_CFG1,
 				0x0C | SD_ASYNC_FIFO_NOT_RST,
@@ -1155,6 +1156,7 @@ static void sdmmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 		host->vpclk = true;
 		host->double_clk = false;
 		break;
+	case MMC_TIMING_MMC_DDR52:
 	case MMC_TIMING_UHS_DDR50:
 	case MMC_TIMING_UHS_SDR25:
 		host->ssc_depth = RTSX_SSC_DEPTH_1M;