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/ls1021aqds_ddr4_nor_defconfig b/configs/ls1021aqds_ddr4_nor_defconfig
index db4e01e..b115c44 100644
--- a/configs/ls1021aqds_ddr4_nor_defconfig
+++ b/configs/ls1021aqds_ddr4_nor_defconfig
@@ -49,6 +49,8 @@
 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_SPL_SYS_I2C_LEGACY=y
 CONFIG_I2C_SET_DEFAULT_BUS_NUM=y