spl: Introduce SoC specific init function

Some architectures use spl_board_init() in their SoC specific
implementation. Board developers should be able to add board specific
implementation via spl_board_init(). Hence, introduce a spl_soc_init()
method which is called right before spl_board_init() for SoC
specific implementation.

Signed-off-by: Lukas Funke <lukas.funke@weidmueller.com>
Reviewed-by: Devarsh Thakkar <devarsht@ti.com>
Link: https://lore.kernel.org/r/20240327121153.2455126-2-lukas.funke-oss@weidmueller.com
Signed-off-by: Michal Simek <michal.simek@amd.com>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index 46bacad..0f7797b 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -272,6 +272,13 @@
 	help
 	  The address in memory that SPL will be running from.
 
+config SPL_SOC_INIT
+	bool "Call SoC-specific initialization in SPL"
+	help
+	  If this option is enabled, U-Boot will call the function
+	  spl_soc_init() from board_init_r(). This function should be
+	  provided by the SoC vendor.
+
 config SPL_BOARD_INIT
 	bool "Call board-specific initialization in SPL"
 	help