fsl_ddr: Move DDR config options to driver Kconfig

Create driver/ddr/fsl/Kconfig and move existing options. Clean up
existing macros.

Signed-off-by: York Sun <york.sun@nxp.com>
[trini: Migrate sbc8641d, xpedite537x and MPC8536DS, run a moveconfig.py -s]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/ls1046aqds_nand_defconfig b/configs/ls1046aqds_nand_defconfig
index 74fcd4a..ebb1b5e 100644
--- a/configs/ls1046aqds_nand_defconfig
+++ b/configs/ls1046aqds_nand_defconfig
@@ -4,7 +4,7 @@
 CONFIG_FIT=y
 CONFIG_FIT_VERBOSE=y
 CONFIG_OF_BOARD_SETUP=y
-CONFIG_SYS_EXTRA_OPTIONS="SYS_FSL_DDR4,RAMBOOT_PBL,SPL_FSL_PBL"
+CONFIG_SYS_EXTRA_OPTIONS="RAMBOOT_PBL,SPL_FSL_PBL"
 CONFIG_NAND_BOOT=y
 CONFIG_BOOTDELAY=10
 CONFIG_SPL=y