spl: Rename SYS_SPL_ARGS_ADDR to SPL_PAYLOAD_ARGS_ADDR

Rename this so that SPL is first, as per U-Boot convention. Also add
PAYLOAD_ since this is where in memory the parameters for the payload
have been stored.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/xilinx_zynq_virt_defconfig b/configs/xilinx_zynq_virt_defconfig
index 16c127b..817fb41 100644
--- a/configs/xilinx_zynq_virt_defconfig
+++ b/configs/xilinx_zynq_virt_defconfig
@@ -43,7 +43,7 @@
 CONFIG_SPL_FS_LOAD_ARGS_NAME="system.dtb"
 CONFIG_SPL_FPGA=y
 CONFIG_SPL_OS_BOOT=y
-CONFIG_SYS_SPL_ARGS_ADDR=0x10000000
+CONFIG_SPL_PAYLOAD_ARGS_ADDR=0x10000000
 CONFIG_SPL_SPI_LOAD=y
 CONFIG_SYS_SPI_U_BOOT_OFFS=0x100000
 CONFIG_SYS_MAXARGS=32