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/gwventana_nand_defconfig b/configs/gwventana_nand_defconfig
index 453662c..3f0cb19 100644
--- a/configs/gwventana_nand_defconfig
+++ b/configs/gwventana_nand_defconfig
@@ -50,7 +50,7 @@
 CONFIG_SPL_I2C=y
 CONFIG_SPL_NAND_SUPPORT=y
 CONFIG_SPL_OS_BOOT=y
-CONFIG_SYS_SPL_ARGS_ADDR=0x18000000
+CONFIG_SPL_PAYLOAD_ARGS_ADDR=0x18000000
 CONFIG_SYS_NAND_SPL_KERNEL_OFFS=0x1200000
 CONFIG_SPL_FALCON_BOOT_MMCSD=y
 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR=0x1000