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/common/spl/Kconfig b/common/spl/Kconfig
index b9d96fb..4632359 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -1063,7 +1063,7 @@
 	  Enable booting directly to an OS from SPL.
 	  for more info read doc/README.falcon
 
-config SYS_SPL_ARGS_ADDR
+config SPL_PAYLOAD_ARGS_ADDR
 	hex "Address in memory to load 'args' file for Falcon Mode to"
 	depends on SPL_OS_BOOT
 	default 0x88000000 if ARCH_OMAP2PLUS