kconfig: Deprecate BOOTLOADER_SRAM_SIZE

This Kconfig is seemingly unused with exception to a single board,
whose maintainers have been unresponsive for a long time. It is
not useful to any other board and can be set in dts, therefore
deprecate it and schedule removal after the Zephyr 3.7 release

Signed-off-by: Jamie McCrae <[email protected]>

Kconfig.zephyr

@@ -872,7 +872,7 @@ config IS_BOOTLOADER
 	  a separate Zephyr image payload.
 
 config BOOTLOADER_SRAM_SIZE
-	int "SRAM reserved for bootloader"
+	int "SRAM reserved for bootloader [DEPRECATED]"
 	default 0
 	depends on !XIP || IS_BOOTLOADER
 	depends on ARM || XTENSA
@@ -883,6 +883,20 @@ config BOOTLOADER_SRAM_SIZE
 	  - Zephyr is a !XIP image, which implicitly assumes existence of a
 	  bootloader that loads the Zephyr !XIP image onto SRAM.
 
+	  This option is deprecated, users should transition to using DTS to set this, if needed.
+	  To be removed after Zephyr 3.7 release.
+
+config BOOTLOADER_SRAM_SIZE_DEPRECATED
+	bool
+	default y
+	select DEPRECATED
+	depends on BOOTLOADER_SRAM_SIZE != 0
+	depends on !XIP || IS_BOOTLOADER
+	depends on ARM || XTENSA
+	help
+	  Non-prompt symbol to indicate that the deprecated BOOTLOADER_SRAM_SIZE Kconfig has a
+	  non-0 value. Please transition to using devicetree.
+
 config BOOTLOADER_ESP_IDF
 	bool "ESP-IDF bootloader support"
 	depends on SOC_FAMILY_ESP32 && !BOOTLOADER_MCUBOOT && !MCUBOOT