Migrate CUSTOM_SYS_INIT_SP_ADDR to Kconfig using system-constants.h

- Make all users of CUSTOM_SYS_INIT_SP_ADDR reference SYS_INIT_SP_ADDR
- Introduce HAS_CUSTOM_SYS_INIT_SP_ADDR to allow for setting the stack
  pointer directly, otherwise we use the common calculation.
- On some platforms that were using the standard calculation but did not
  set CONFIG_SYS_INIT_RAM_SIZE / CONFIG_SYS_INIT_RAM_ADDR, set them.
- On a small number of platforms that were not subtracting
  GENERATED_GBL_DATA_SIZE do so now via the standard calculation.
- CONFIG_SYS_INIT_SP_OFFSET is now widely unused, so remove it from most
  board config header files.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/include/configs/smartweb.h b/include/configs/smartweb.h
index 3b2803f..533129f 100644
--- a/include/configs/smartweb.h
+++ b/include/configs/smartweb.h
@@ -109,8 +109,8 @@
  * leaving the correct space for initial global data structure above that
  * address while providing maximum stack area below.
  */
-#define CONFIG_SYS_INIT_SP_ADDR \
-	(ATMEL_BASE_SRAM1 + 0x1000 - GENERATED_GBL_DATA_SIZE)
+#define CONFIG_SYS_INIT_RAM_SIZE	0x1000
+#define CONFIG_SYS_INIT_RAM_ADDR	ATMEL_BASE_SRAM1
 
 /* Defines for SPL */