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/mccmon6_nor_defconfig b/configs/mccmon6_nor_defconfig
index 88a72b3..5e8fbd0 100644
--- a/configs/mccmon6_nor_defconfig
+++ b/configs/mccmon6_nor_defconfig
@@ -29,7 +29,7 @@
 CONFIG_SPL_ENV_SUPPORT=y
 CONFIG_SPL_NOR_SUPPORT=y
 CONFIG_SPL_OS_BOOT=y
-CONFIG_SYS_SPL_ARGS_ADDR=0x18000000
+CONFIG_SPL_PAYLOAD_ARGS_ADDR=0x18000000
 CONFIG_SYS_OS_BASE=0x8180000
 CONFIG_SYS_MAXARGS=32
 CONFIG_SYS_PBSIZE=532