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/arch/arm/Kconfig b/arch/arm/Kconfig
index 698370b..52a9f39 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -770,6 +770,7 @@
 	select ARCH_LS1021A
 	select ARCH_SUPPORT_PSCI
 	select LS1_DEEP_SLEEP
+	select SYS_FSL_DDR
 
 config TARGET_LS1021ATWR
 	bool "Support ls1021atwr"