powerpc: P1010RDB: Remove macros CONFIG_P1010RDB_PA and CONFIG_P1010RDB_PB

Remove CONFIG_P1010RDB_PA and CONFIG_P1010RDB_PB and split TARGET_P1010RDB
to TARGET_P1010RDB_PA and TARGET_P1010RDB_PB in Kconfig.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/board/freescale/p1010rdb/Kconfig b/board/freescale/p1010rdb/Kconfig
index b0a7a8d..159bcc4 100644
--- a/board/freescale/p1010rdb/Kconfig
+++ b/board/freescale/p1010rdb/Kconfig
@@ -1,4 +1,4 @@
-if TARGET_P1010RDB
+if TARGET_P1010RDB_PA || TARGET_P1010RDB_PB
 
 config SYS_BOARD
 	default "p1010rdb"