sdhci_fsl_fdt: Fix tuning code
- Some of the register writes were already done in the generic tuning code. Remove them.
- Increase the polling timeout. The previous value is probably fine, but since timeouts are treated as fatal errors increasing it to 200ms won't hurt.
- Rework the HS400 switching code. Make sure that the switch happens at the right time. Reset the DLL0 block. We need to do that if u-boot has previously configured the controller in HS400 mode.
- Check current timing before tuning. The tuning devmethod is always called, even for timings that don't require the tuning procedure.
- Rework software tuning routine code. Use inner formula for clock divider calculation, as previous one was incorrect.
- Implement custom re-tune procedure.
Co-authored-by: Hubert Mazur <firstname.lastname@example.org>
Obtained from: Semihalf
Sponsored by: Alstom Group
Differential Revision: https://reviews.freebsd.org/D34027