drivers/ddr/fsl: Fix workaround for A009803

Wrong field was masked in this workaround due to wrong endianness. The
impacted SoCs have big-endian.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/drivers/ddr/fsl/fsl_ddr_gen4.c b/drivers/ddr/fsl/fsl_ddr_gen4.c
index b3a27ec..7df9178 100644
--- a/drivers/ddr/fsl/fsl_ddr_gen4.c
+++ b/drivers/ddr/fsl/fsl_ddr_gen4.c
@@ -210,7 +210,7 @@
 	if (regs->ddr_sdram_cfg_2 & SDRAM_CFG2_AP_EN) {
 		if (regs->ddr_sdram_cfg & SDRAM_CFG_RD_EN) { /* for RDIMM */
 			ddr_out32(&ddr->ddr_sdram_rcw_2,
-				  regs->ddr_sdram_rcw_2 & ~0x0f000000);
+				  regs->ddr_sdram_rcw_2 & ~0xf0);
 		}
 		ddr_out32(&ddr->err_disable, regs->err_disable |
 			  DDR_ERR_DISABLE_APED);