ramips: cudy wr1300v1 reduce SPI freq to 10000000

ramips: cudy wr1300v1 reduce SPI freq to 10000000

Reducing SPI flash frequency allows the build to boot on both old variants
with W25Q128 chip and new variants with XM25QH128C chip.

The old 80000000 value only boots on devices with the W25Q128 flash.

This is also the change Cudy themselves made in their openwrt builds and
their .dts file.

Removed m25p,fast-read as it is not needed with slower speeds.

Signed-off-by: Filip Milivojevic <zekica@gmail.com>