arm: mach-k3: Add basic support for J784S4 SoC definition

Add J784S4 initialization files for initial SPL boot.

config SYS_K3_MCU_SCRATCHPAD_BASE default value is same
for J721E, J721S2, J784S4. So combined them into a single
default.

Signed-off-by: Hari Nagalla <hnagalla@ti.com>
[ add firewall configurations and change the R5 MCU scratchpad ]
Signed-off-by: Manorit Chawdhry <m-chawdhry@ti.com>
Signed-off-by: Dasnavis Sabiya <sabiya.d@ti.com>
Signed-off-by: Apurva Nandan <a-nandan@ti.com>
Reviewed-by: Neha Malcom Francis <n-francis@ti.com>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com> # AM69-SK
diff --git a/arch/arm/mach-k3/include/mach/spl.h b/arch/arm/mach-k3/include/mach/spl.h
index 3ddc7eb..6f01ab5 100644
--- a/arch/arm/mach-k3/include/mach/spl.h
+++ b/arch/arm/mach-k3/include/mach/spl.h
@@ -30,4 +30,8 @@
 #include "am62a_spl.h"
 #endif
 
+#ifdef CONFIG_SOC_K3_J784S4
+#include "j784s4_spl.h"
+#endif
+
 #endif /* _ASM_ARCH_SPL_H_ */