arm: K3: am654: Add support for boot device detection

AM654 allows for booting from primary or backup boot media.
Both media can be chosen individually based on switch settings.
ROM looks for a valid image in primary boot media, if not found
then looks in backup boot media. In order to pass this boot media
information to boot loader, ROM stores a value at a particular
address. Add support for reading this information and determining
the boot media correctly.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
Signed-off-by: Vignesh R <vigneshr@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/mach-k3/Kconfig b/arch/arm/mach-k3/Kconfig
index 9892f57..1380013 100644
--- a/arch/arm/mach-k3/Kconfig
+++ b/arch/arm/mach-k3/Kconfig
@@ -40,4 +40,11 @@
 	help
 	  Describes the size of MCU Scratchpad RAM.
 
+config SYS_K3_BOOT_PARAM_TABLE_INDEX
+	hex
+	default 0x41c7fbfc if SOC_K3_AM6
+	help
+	  Address at which ROM stores the value which determines if SPL
+	  is booted up by primary boot media or secondary boot media.
+
 endif