This patch documents support for STM32H7 Real Time Clock.
It introduces a new compatible and rework clock definitions.
On STM32H7 we have a 'pclk' clock for register access, in addition to
the 'rtc_ck' clock.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>