Add improvements for read and set offset functions.
The basic functionality is still the same, but offset correction values
are now updated to match with expected.

The RTC calibration value operates with full ticks,
and fractional ticks which are a 1/16 of a full tick.
The 16 lowest bits in the calibration registers are for the full ticks
and value matches the external oscillator in Hz. Through that,
the maximum and minimum offset values can be calculated dynamically,
as they depend on the input frequency used.

For docs on the calibration register, see
https://docs.amd.com/r/en-US/ug1087-zynq-ultrascale-registers/CALIB_READ-RTC-Register

Signed-off-by: Tomas Melin <tomas.melin@vaisala.com>
---
Tomas Melin (4):
      rtc: zynqmp: correct frequency value
      rtc: zynqmp: rework read_offset
      rtc: zynqmp: rework set_offset
      rtc: zynqmp: use dynamic max and min offset ranges

 drivers/rtc/rtc-zynqmp.c | 65 ++++++++++++++++++++++++------------------------
 1 file changed, 33 insertions(+), 32 deletions(-)
---
base-commit: cd635e33b0113287c94021be53d2a7c61a1614e9
change-id: 20251201-zynqmp-rtc-updates-d260364cc01b

Best regards,
-- 
Tomas Melin <tomas.melin@vaisala.com>