soc: mchp: Update 32KHz programming sequence

    Based upon discussions with HW designers the 32KHz
    programming sequence can be simplified. When FW writes
    a value to the VBAT 32KHz Clock Enable register HW checks
    if the value is the same as the current value. If the same
    the HW does nothing. If different HW begins a sequence to
    switch off the current 32KHz source, revert to ring oscillator,
    and switch to the new source. FW should program the new value
    and then spin until the PCR OSC ID PLL Lock bit goes to 1.

Signed-off-by: Scott Worley <scott.worley@microchip.com>