powerpc: mpc86xx: Convert CONFIG_SYS_FSL_NUM_LAWS to Kconfig option

Use Kconfig instead of defining this macro in header file.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/arch/powerpc/cpu/mpc86xx/Kconfig b/arch/powerpc/cpu/mpc86xx/Kconfig
index 42b2ed2..11afffa 100644
--- a/arch/powerpc/cpu/mpc86xx/Kconfig
+++ b/arch/powerpc/cpu/mpc86xx/Kconfig
@@ -47,6 +47,12 @@
 		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.
+config SYS_FSL_NUM_LAWS
+	int "Number of local access windows"
+	default 10 if ARCH_MPC8610 || ARCH_MPC8641
+	help
+		Number of local access windows. This is fixed per SoC.
+		If not sure, do not change.
 
 source "board/freescale/mpc8610hpcd/Kconfig"
 source "board/freescale/mpc8641hpcn/Kconfig"