arm: mvebu: Espressobin: Detect presence of emmc at runtime

Try to initialize emmc in board_late_init() and if it fails then we know
that emmc device is not connected.

This allows to use in U-Boot just one DTS file for all Espressobin variants
and also to correctly set fdtfile env variable for Linux kernel.

Signed-off-by: Pali Rohár <pali@kernel.org>
Tested-by: Gérald Kerma <gerald@gk2.net>
Reviewed-by: Andre Heider <a.heider@gmail.com>
diff --git a/board/Marvell/mvebu_armada-37xx/board.c b/board/Marvell/mvebu_armada-37xx/board.c
index 73d69e0..f67b04b 100644
--- a/board/Marvell/mvebu_armada-37xx/board.c
+++ b/board/Marvell/mvebu_armada-37xx/board.c
@@ -8,6 +8,7 @@
 #include <env.h>
 #include <i2c.h>
 #include <init.h>
+#include <mmc.h>
 #include <phy.h>
 #include <asm/io.h>
 #include <asm/arch/cpu.h>
@@ -83,6 +84,7 @@
 #ifdef CONFIG_BOARD_LATE_INIT
 int board_late_init(void)
 {
+	struct mmc *mmc_dev;
 	bool ddr4, emmc;
 
 	if (env_get("fdtfile"))
@@ -95,7 +97,9 @@
 	ddr4 = ((readl(A3700_CH0_MC_CTRL2_REG) >> A3700_MC_CTRL2_SDRAM_TYPE_OFFS)
 		& A3700_MC_CTRL2_SDRAM_TYPE_MASK) == A3700_MC_CTRL2_SDRAM_TYPE_DDR4;
 
-	emmc = of_machine_is_compatible("globalscale,espressobin-emmc");
+	/* eMMC is mmc dev num 1 */
+	mmc_dev = find_mmc_device(1);
+	emmc = (mmc_dev && mmc_init(mmc_dev) == 0);
 
 	if (ddr4 && emmc)
 		env_set("fdtfile", "marvell/armada-3720-espressobin-v7-emmc.dtb");