stm32mp1: Add remoteproc support for m4 coprocessor

Alignment with kernel patch proposal for binding:

[PATCH v4 0/8] stm32 m4 remoteproc on STM32MP157c
https://lkml.org/lkml/2019/5/14/159

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
7 files changed