powerpc: P5020DS: Remove macro CONFIG_P5020DS

Use CONFIG_TARGET_P5020DS instead.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/board/freescale/common/Makefile b/board/freescale/common/Makefile
index c26ada1..73a722a 100644
--- a/board/freescale/common/Makefile
+++ b/board/freescale/common/Makefile
@@ -55,7 +55,7 @@
 obj-$(CONFIG_P2020DS)		+= ics307_clk.o
 obj-$(CONFIG_TARGET_P3041DS)		+= ics307_clk.o
 obj-$(CONFIG_TARGET_P4080DS)		+= ics307_clk.o
-obj-$(CONFIG_P5020DS)		+= ics307_clk.o
+obj-$(CONFIG_TARGET_P5020DS)		+= ics307_clk.o
 obj-$(CONFIG_P5040DS)		+= ics307_clk.o
 obj-$(CONFIG_VSC_CROSSBAR)    += vsc3316_3308.o
 obj-$(CONFIG_IDT8T49N222A)	+= idt8t49n222a_serdes_clk.o
@@ -68,7 +68,7 @@
 obj-$(CONFIG_TARGET_P2041RDB)	+= p_corenet/
 obj-$(CONFIG_TARGET_P3041DS)	+= p_corenet/
 obj-$(CONFIG_TARGET_P4080DS)	+= p_corenet/
-obj-$(CONFIG_P5020DS)	+= p_corenet/
+obj-$(CONFIG_TARGET_P5020DS)	+= p_corenet/
 obj-$(CONFIG_P5040DS)	+= p_corenet/
 
 obj-$(CONFIG_LAYERSCAPE_NS_ACCESS)	+= ns_access.o