board: helios-4: add config fragment for spi booting

Add a config fragment with required differences for booting from spi
flash instead of sd-card (default).

Settings for environment location are based on vendor u-boot:
https://github.com/kobol-io/u-boot/blob/helios4/include/configs/helios4.h#L59

The fragment can be applied on top of helios4_defconfig by make:
make helios4_defconfig spiboot.config

Signed-off-by: Josua Mayer <josua@solid-run.com>

diff --git a/board/kobol/helios4/spiboot.config b/board/kobol/helios4/spiboot.config
new file mode 100644 (file)
index 0000000..5ffb7d2
--- /dev/null
+++ b/board/kobol/helios4/spiboot.config
@@ -0,0 +1,4 @@
+CONFIG_MVEBU_SPL_BOOT_DEVICE_SPI=y
+# CONFIG_MVEBU_SPL_BOOT_DEVICE_MMC is not set
+CONFIG_ENV_OFFSET=0x100000
+CONFIG_ENV_SECT_SIZE=0x10000