powerpc: MPC8541CDS: Remove macro CONFIG_MPC8541CDS

Replace with CONFIG_TARGET_MPC8541CDS from Kconfig.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/board/freescale/common/Makefile b/board/freescale/common/Makefile
index db36e53..e01df42 100644
--- a/board/freescale/common/Makefile
+++ b/board/freescale/common/Makefile
@@ -45,7 +45,7 @@
 
 obj-$(CONFIG_FSL_DCU_SII9022A)    += dcu_sii9022a.o
 
-obj-$(CONFIG_MPC8541CDS)	+= cds_pci_ft.o
+obj-$(CONFIG_TARGET_MPC8541CDS)	+= cds_pci_ft.o
 obj-$(CONFIG_TARGET_MPC8548CDS)	+= cds_pci_ft.o
 obj-$(CONFIG_MPC8555CDS)	+= cds_pci_ft.o