board: st: remove board_mtdparts_default

Remove the function board_mtdparts_default and the associated file
or configs, only used by the CONFIG_SYS_MTDPARTS_RUNTIME now removed.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
3 files changed