The RTC in rp2 can store any, even wrong, number as a weekday in RTC. It
was, however, discussed in #7394 that we would like to unify all ports and
use 0 as Monday, not Sunday in the machine.RTC implementation.
This patch makes sure that the default date set in RTC is adheres to this
convention. It also fixes the example in quickref to use proper weekday to
avoid confusion.
Signed-off-by: Krzysztof Adamski <k@japko.eu>
