drivers: stm32_fmc2_nand: move to new bindings

FMC node bindings are modified to add EBI controller node.
FMC driver and associated device tree files are modified
to support these new bindings.

Change-Id: I4bf201e96a1aca20957e0dac3a3b87caadd05bdc
Signed-off-by: Christophe Kerello <christophe.kerello@st.com>
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>