configs: fsl: move DDR specific defines to Kconfig

Moves below DDR specific defines to Kconfig:

CONFIG_FSL_DDR_BIST
CONFIG_FSL_DDR_FIRST_SLOT_QUAD_CAPABLE
CONFIG_FSL_DDR_INTERACTIVE
CONFIG_FSL_DDR_SYNC_REFRESH

Signed-off-by: Rajesh Bhagat <rajesh.bhagat@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
diff --git a/arch/powerpc/cpu/mpc86xx/Kconfig b/arch/powerpc/cpu/mpc86xx/Kconfig
index 2cc180d..0f25305 100644
--- a/arch/powerpc/cpu/mpc86xx/Kconfig
+++ b/arch/powerpc/cpu/mpc86xx/Kconfig
@@ -21,6 +21,7 @@
 config TARGET_MPC8641HPCN
 	bool "Support MPC8641HPCN"
 	select ARCH_MPC8641
+	select FSL_DDR_INTERACTIVE
 	imply SCSI
 
 config TARGET_XPEDITE517X