Issue:
    - # hwclock -w
      hwclock: RTC_SET_TIME: Invalid argument

Why:
    - Relative commit: 8b9f9d4d

 ("regmap: verify if register is
      writeable before writing operations"), this patch
      will always check for unwritable registers, it will compare reg
      with max_register in regmap_writeable.

    - The pcf85363/pcf85263 has the capability of address wrapping
      which means if you access an address outside the allowed range
      (0x00-0x2f) hardware actually wraps the access to a lower address.
      The rtc-pcf85363 driver will use this feature to configure the time
      and execute 2 actions in the same i2c write operation (stopping the
      clock and configure the time). However the driver has also
      configured the `regmap maxregister` protection mechanism that will
      block accessing addresses outside valid range (0x00-0x2f).

How:
    - Split of writing regs to two parts, first part writes control
      registers about stop_enable and resets, second part writes
      RTC time and date registers.

Signed-off-by: Biwen Li <biwen.li@nxp.com>
Link: https://lore.kernel.org/r/20190829021418.4607-1-biwen.li@nxp.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>