configs: fsl: move via specific defines to Kconfig

Moves below via specific defines to Kconfig:

	CONFIG_FSL_VIA

Signed-off-by: Rajesh Bhagat <rajesh.bhagat@nxp.com>
[Rebased]
Signed-off-by: Priyanka Jain <priyanka.jain@nxp.com>
diff --git a/arch/powerpc/cpu/mpc85xx/Kconfig b/arch/powerpc/cpu/mpc85xx/Kconfig
index 6f90518..1a4e0b9 100644
--- a/arch/powerpc/cpu/mpc85xx/Kconfig
+++ b/arch/powerpc/cpu/mpc85xx/Kconfig
@@ -51,14 +51,17 @@
 config TARGET_MPC8541CDS
 	bool "Support MPC8541CDS"
 	select ARCH_MPC8541
+	select FSL_VIA
 
 config TARGET_MPC8548CDS
 	bool "Support MPC8548CDS"
 	select ARCH_MPC8548
+	select FSL_VIA
 
 config TARGET_MPC8555CDS
 	bool "Support MPC8555CDS"
 	select ARCH_MPC8555
+	select FSL_VIA
 
 config TARGET_MPC8568MDS
 	bool "Support MPC8568MDS"
@@ -1409,6 +1412,9 @@
 		Defines divider of platform clock(clock input to
 		eLBC controller).
 
+config FSL_VIA
+	bool
+
 source "board/freescale/corenet_ds/Kconfig"
 source "board/freescale/mpc8541cds/Kconfig"
 source "board/freescale/mpc8548cds/Kconfig"