feat(stm32mp1-fdts): move RNG1 to CSI to improve random generation

LSI was too slow to provide enough random numbers (limited
to 6ms for 16 bytes production). Switch to CSI that allow
to get the RNG fifo ready in less than 50µs.

Signed-off-by: Lionel Debieve <lionel.debieve@foss.st.com>
Change-Id: I76d1fe58e2f4d5416a96f48123ae36bd82d8a8ee
8 files changed