boards/afcz: more verbose clock diagnostics + reduce Si57X gain to avoid intermittent clock glitches during vco tuning

rxts_calibrator: increase t24p tollerance to 2ns to avoid recalibrating with minor t24p offsets (~200ps seen in sis83k)

This reverts commit 539ca7ba.

Signed-off-by: Kinga Wujek <dev_public@wujek.eu>

This throws a warning in gcc-lm32-elf version 4, and a error in version 10.
NO PPSI update!