treewide: Migrate CONFIG_FSL_ESDHC to Kconfig

Migrate the CONFIG_FSL_ESDHC option to Kconfig.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
diff --git a/configs/mx6sllevk_defconfig b/configs/mx6sllevk_defconfig
index 39c1cef..3c5da8c 100644
--- a/configs/mx6sllevk_defconfig
+++ b/configs/mx6sllevk_defconfig
@@ -28,6 +28,7 @@
 CONFIG_DM_GPIO=y
 CONFIG_DM_I2C=y
 CONFIG_DM_MMC=y
+CONFIG_FSL_ESDHC=y
 CONFIG_PINCTRL=y
 CONFIG_PINCTRL_IMX6=y
 CONFIG_DM_PMIC=y