dt-bindings: memory-controller: st,stm32: Fix st,fmc2_ebi-cs-write-address-setup-ns

The property st,fmc2_ebi-cs-write-address-setup-ns should really be
st,fmc2-ebi-cs-write-address-setup-ns (there is underscore _ between
fmc2 and ebi and there should be a dash - instead). This is a remnant
from conversion of old non-upstream bindings. Fix it.

Signed-off-by: Marek Vasut <marex@denx.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220926222003.527171-1-marex@denx.de