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/r5/Makefile b/arch/arm/mach-k3/r5/Makefile
index b99199d..b666ed3 100644
--- a/arch/arm/mach-k3/r5/Makefile
+++ b/arch/arm/mach-k3/r5/Makefile
@@ -8,6 +8,7 @@
 obj-$(CONFIG_SOC_K3_J721S2) += j721s2/
 obj-$(CONFIG_SOC_K3_AM625) += am62x/
 obj-$(CONFIG_SOC_K3_AM62A7) += am62ax/
+obj-$(CONFIG_SOC_K3_J784S4) += j784s4/
 
 obj-y += lowlevel_init.o
 obj-y += r5_mpu.o