configs: Migrate CONFIG_SYS_MAX_FLASH_BANKS to Kconfig

Use moveconfig.py script to convert define CONFIG_SYS_MAX_FLASH_BANKS
and CONFIG_SYS_MAX_FLASH_BANKS_DETECT to Kconfig and move these entries
to defconfigs.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>
[trini: Re-switch to IS_ENABLED check in spi-nor-core.c, re-run migration]
Signed-off-by: Tom Rini <trini@konsulko.com>