Merge tag 'xilinx-for-v2018.05-rc3' of git://git.denx.de/u-boot-microblaze

Xilinx fixes for v2018.05-rc3

- Fix nand initialization
- Runtime ddr detection for static DDR setting
- Enable rewriting env locations
- Sync defconfig for zc770 xm011
- Remove useless ioremap in watchdog
- Check return value from soc_clk_dump()
diff --git a/drivers/mmc/meson_gx_mmc.c b/drivers/mmc/meson_gx_mmc.c
index a2cd5d3..454593e 100644
--- a/drivers/mmc/meson_gx_mmc.c
+++ b/drivers/mmc/meson_gx_mmc.c
@@ -35,6 +35,9 @@
 	uint32_t meson_mmc_clk = 0;
 	unsigned int clk, clk_src, clk_div;
 
+	if (!mmc->clock)
+		return;
+
 	/* 1GHz / CLK_MAX_DIV = 15,9 MHz */
 	if (mmc->clock > 16000000) {
 		clk = SD_EMMC_CLKSRC_DIV2;