[v6,08/12] arm: mvebu: clearfog: add SPI offsets

Add reasonable default SPI offsets and ENV size when configured to
boot from SPI flash.

Signed-off-by: Joel Johnson <mrjoel at lixil.net>
Reviewed-by: Stefan Roese <sr at denx.de>

---

v2 changes:
  - none
v3 changes:
  - none
v4 changes:
  - none
v5 changes:
  - none
v6 changes:
  - none

There was some reasonable concern raised about duplicating config
entries within a board specific config file rather than making
board specific configurations within defconfig. This seems to offer
a more board localized mechanism to provide platform defaults for
core values. As mentioned in the review, this usage seems to match
the Kconfig documented intended usage. As noted at
https://www.kernel.org/doc/html/latest/kbuild/kconfig-language.html:
    "Default values are not limited to the menu entry where
     they are defined. This means the default can be defined
     somewhere else or be overridden by an earlier definition."

Given that there is some dependency variability with these values I
prefer keeping them as Kconfig values, but defer to maintainers.
Notably, for the ENV values in this and a later commit, I'm using a
pattern already in used several other board configs.

---
 board/solidrun/clearfog/Kconfig | 12 ++++++++++++
 1 file changed, 12 insertions(+)