powerpc: MPC8610HPCD: Remove macro CONFIG_MPC8610HPCD

Use TARGET_MPC8610HPCD from Kconfig instead.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/board/freescale/common/pixis.h b/board/freescale/common/pixis.h
index df3cc09..bb0e65e 100644
--- a/board/freescale/common/pixis.h
+++ b/board/freescale/common/pixis.h
@@ -102,7 +102,7 @@
 	u8 res4[25];
 } __attribute__ ((packed)) pixis_t;
 
-#elif defined(CONFIG_MPC8610HPCD)
+#elif defined(CONFIG_TARGET_MPC8610HPCD)
 typedef struct pixis {
 	u8 id;
 	u8 ver;	/* also called arch */