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/configs/sniper_defconfig b/configs/sniper_defconfig
index ef2f49f..4dbe4f1 100644
--- a/configs/sniper_defconfig
+++ b/configs/sniper_defconfig
@@ -9,6 +9,8 @@
 CONFIG_TARGET_SNIPER=y
 CONFIG_SPL=y
 CONFIG_DISTRO_DEFAULTS=y
+CONFIG_HAS_CUSTOM_SYS_INIT_SP_ADDR=y
+CONFIG_CUSTOM_SYS_INIT_SP_ADDR=0x4020ff00
 CONFIG_BOOTCOMMAND="setenv boot_mmc_part ${kernel_mmc_part}; if test reboot-${reboot-mode} = reboot-r; then echo recovery; setenv boot_mmc_part ${recovery_mmc_part}; fi; if test reboot-${reboot-mode} = reboot-b; then echo fastboot; fastboot 0; fi; part start mmc ${boot_mmc_dev} ${boot_mmc_part} boot_mmc_start; part size mmc ${boot_mmc_dev} ${boot_mmc_part} boot_mmc_size; mmc dev ${boot_mmc_dev}; mmc read ${kernel_addr_r} ${boot_mmc_start} ${boot_mmc_size} && bootm ${kernel_addr_r};"
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
 CONFIG_SPL_MAX_SIZE=0xec00