This patch adds FMC2 EBI controller support used by STM32MP SOCs.

Link: https://lore.kernel.org/r/20200924101342.4707-1-alexandre.torgue@st.comSigned-off-by: Christophe Kerello <christophe.kerello@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: Olof Johansson <olof@lixom.net>