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/powerpc/Kconfig b/arch/powerpc/Kconfig
index 853e265..0033c35 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -30,9 +30,13 @@
 config MPC85xx
 	bool "MPC85xx"
 	select CREATE_ARCH_SYMLINK
+	select SYS_FSL_DDR
+	select SYS_FSL_DDR_BE
 
 config MPC86xx
 	bool "MPC86xx"
+	select SYS_FSL_DDR
+	select SYS_FSL_DDR_BE
 
 config 8xx
 	bool "MPC8xx"