powerpc:Rename CONFIG_PBLRCW_CONFIG & CONFIG_SYS_FSL_PBL_PBI

Rename CONFIG_PBLRCW_CONFIG and CONFIG_PBLRCW_CONFIG.

Also add their details in README.

Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/include/configs/T4240QDS.h b/include/configs/T4240QDS.h
index c96df54..1f1177b 100644
--- a/include/configs/T4240QDS.h
+++ b/include/configs/T4240QDS.h
@@ -21,8 +21,8 @@
 #ifdef CONFIG_RAMBOOT_PBL
 #define CONFIG_RAMBOOT_TEXT_BASE	CONFIG_SYS_TEXT_BASE
 #define CONFIG_RESET_VECTOR_ADDRESS	0xfffffffc
-#define CONFIG_PBLPBI_CONFIG $(SRCTREE)/board/freescale/t4qds/t4_pbi.cfg
-#define CONFIG_PBLRCW_CONFIG $(SRCTREE)/board/freescale/t4qds/t4_rcw.cfg
+#define CONFIG_SYS_FSL_PBL_PBI $(SRCTREE)/board/freescale/t4qds/t4_pbi.cfg
+#define CONFIG_SYS_FSL_PBL_RCW $(SRCTREE)/board/freescale/t4qds/t4_rcw.cfg
 #endif
 
 #ifdef CONFIG_SRIO_PCIE_BOOT_SLAVE