nxp: Migrate a number of DDR related symbols to Kconfig

- Guard most of the options in drivers/ddr/fsl/Kconfig with
  SYS_FSL_DDR || SYS_FSL_MMDC.
- Migrate FSL_DMA, DDR_ECC, DDR_ECC_CMD, and ECC_INIT_VIA_DDRCONTROLLER
  to Kconfig.
- Clean up the logic for including the DDR_ECC_CMD code.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/ls1046aqds_nand_defconfig b/configs/ls1046aqds_nand_defconfig
index 171e9c4..93c0fcf 100644
--- a/configs/ls1046aqds_nand_defconfig
+++ b/configs/ls1046aqds_nand_defconfig
@@ -56,6 +56,8 @@
 CONFIG_SATA_CEVA=y
 CONFIG_FSL_CAAM=y
 CONFIG_DYNAMIC_DDR_CLK_FREQ=y
+CONFIG_DDR_ECC=y
+CONFIG_ECC_INIT_VIA_DDRCONTROLLER=y
 CONFIG_DM_I2C=y
 CONFIG_I2C_SET_DEFAULT_BUS_NUM=y
 CONFIG_SYS_I2C_EEPROM_ADDR=0x57