[][drivers: spi-mt65xx: Move chip config to driver private]

[Description]
Change chip config to driver private data.
If we use global data and use 2 or more SPI devices, they will share
the same tick_dly & sample_sel value. In most situations, those SPI
devices will use different tick_dly values. (After calibration)

[Release-log]
N/A

Change-Id: I9b893da26825a3e4974aed8249e58ff43d565f2d
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6092044
1 file changed