arm: mvebu: turris_omnia: Disable ext4 write support in defconfig

Turris Omnia defconfig is nearing image size limit. Disable ext4 write
support to reserve space for more important stuff.

This reduces the size of the KWB image by ~19 KiB.

If in the future U-Boot supports compressing itself and decompressing
on load, we may enable this again.

Signed-off-by: Marek BehĂșn <kabel@kernel.org>
1 file changed