Convert CONFIG_SYS_SPL_ARGS_ADDR to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_SPL_ARGS_ADDR

In doing so, we also consistently use this variable for SPL_OS_BOOT and
not CONFIG_SYS_FDT_BASE in some cases.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index dfbda1b..71b2600 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -1188,6 +1188,14 @@
 	  Enable booting directly to an OS from SPL.
 	  for more info read doc/README.falcon
 
+config SYS_SPL_ARGS_ADDR
+	hex "Address in memory to load 'args' file for Falcon Mode to"
+	depends on SPL_OS_BOOT
+	default 0x88000000 if ARCH_OMAP2PLUS
+	help
+	  Address in memory where the 'args' file, typically a device tree
+	  will be loaded in to memory.
+
 if SPL_OS_BOOT
 config SYS_OS_BASE
 	hex "addr, where OS is found"
diff --git a/common/spl/spl_nor.c b/common/spl/spl_nor.c
index 067a2d4..7986e93 100644
--- a/common/spl/spl_nor.c
+++ b/common/spl/spl_nor.c
@@ -74,8 +74,8 @@
 			       (void *)(CONFIG_SYS_OS_BASE +
 					sizeof(struct image_header)),
 			       spl_image->size);
-#ifdef CONFIG_SYS_FDT_BASE
-			spl_image->arg = (void *)CONFIG_SYS_FDT_BASE;
+#ifdef CONFIG_SYS_SPL_ARGS_ADDR
+			spl_image->arg = (void *)CONFIG_SYS_SPL_ARGS_ADDR;
 #endif
 
 			return 0;
diff --git a/common/spl/spl_xip.c b/common/spl/spl_xip.c
index 33863fe..e9a40b0 100644
--- a/common/spl/spl_xip.c
+++ b/common/spl/spl_xip.c
@@ -14,7 +14,7 @@
 {
 #if CONFIG_IS_ENABLED(OS_BOOT)
 	if (!spl_start_uboot()) {
-		spl_image->arg = (void *)CONFIG_SYS_FDT_BASE;
+		spl_image->arg = (void *)CONFIG_SYS_SPL_ARGS_ADDR;
 		spl_image->name = "Linux";
 		spl_image->os = IH_OS_LINUX;
 		spl_image->load_addr = CONFIG_SYS_LOAD_ADDR;