am33xx: Define common init stack pointer address in Kconfig

The init stack pointer was defined to the same value in each AM33xx
board defconfig. Move the common definition to the Kconfig option
declaration instead.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Reviewed-by: Tom Rini <trini@konsulko.com>
Tested-by: Derald D. Woods <woods.technical@gmail.com>
diff --git a/Kconfig b/Kconfig
index 98175a8..45656e9 100644
--- a/Kconfig
+++ b/Kconfig
@@ -236,7 +236,7 @@
 config HAS_CUSTOM_SYS_INIT_SP_ADDR
 	bool "Use a custom location for the initial stack pointer address"
 	depends on ARC || (ARM && !INIT_SP_RELATIVE) || MIPS || PPC || RISCV
-	default y if OMAP34XX
+	default y if OMAP34XX || AM33XX
 	default y if TFABOOT
 	help
 	  Typically, we use an initial stack pointer address that is calculated
@@ -251,6 +251,7 @@
 	hex "Static location for the initial stack pointer"
 	depends on HAS_CUSTOM_SYS_INIT_SP_ADDR
 	default 0x4020ff00 if OMAP34XX
+	default 0x4030ff00 if AM33XX
 	default TEXT_BASE if TFABOOT
 
 config SYS_MALLOC_F