mediatek: drop spi cal for Keenetic KN-(3711/3811/3911)
In the original DTS from the device firmware, there are
no entries that enable SPI calibration. Therefore, it
should be disabled.
Signed-off-by: Maxim Anisimov <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/21635
Signed-off-by: Hauke Mehrtens <[email protected]>