powerpc: Use the poison value of 0xdeadbeef directly in DDR init

On p1_p2_rdb_pc platforms, we set ddr_data_init to the "poison" value of
0xdeadbeef rather than a real calculated / derived value.  Do this
directly and comment rather than via CONFIG.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/freescale/p1_p2_rdb_pc/ddr.c b/board/freescale/p1_p2_rdb_pc/ddr.c
index be803dd..038e673 100644
--- a/board/freescale/p1_p2_rdb_pc/ddr.c
+++ b/board/freescale/p1_p2_rdb_pc/ddr.c
@@ -227,7 +227,7 @@
 		.ddr_sdram_mode_2 = CONFIG_SYS_DDR_MODE_2,
 		.ddr_sdram_md_cntl = CONFIG_SYS_DDR_MODE_CONTROL,
 		.ddr_sdram_interval = CONFIG_SYS_DDR_INTERVAL,
-		.ddr_data_init = CONFIG_SYS_DDR_DATA_INIT,
+		.ddr_data_init = 0xdeadbeef, /* Poison value */
 		.ddr_sdram_clk_cntl = CONFIG_SYS_DDR_CLK_CTRL,
 		.ddr_init_addr = CONFIG_SYS_DDR_INIT_ADDR,
 		.ddr_init_ext_addr = CONFIG_SYS_DDR_INIT_EXT_ADDR,