powerpc: mpc86xx: Convert CONFIG_SYS_CCSRBAR_DEFAULT to Kconfig option

Move default value definitions to Kconfig SYS_CCSRBAR_DEFAULT.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/arch/powerpc/cpu/mpc86xx/Kconfig b/arch/powerpc/cpu/mpc86xx/Kconfig
index 98fb702..57e7476 100644
--- a/arch/powerpc/cpu/mpc86xx/Kconfig
+++ b/arch/powerpc/cpu/mpc86xx/Kconfig
@@ -32,6 +32,15 @@
 config ARCH_MPC8641
 	bool
 
+config SYS_CCSRBAR_DEFAULT
+	hex "Default CCSRBAR address"
+	default 0xff700000 if ARCH_MPC8610 || ARCH_MPC8641
+	help
+		Default value of CCSRBAR comes from power-on-reset. It
+		is fixed on each SoC. Some SoCs can have different value
+		if changed by pre-boot regime. The value here must match
+		the current value in SoC. If not sure, do not change.
+
 source "board/freescale/mpc8610hpcd/Kconfig"
 source "board/freescale/mpc8641hpcn/Kconfig"
 source "board/sbc8641d/Kconfig"