ARM: dts: stm32: Update qspi bindings for stm32f746

Align qspi bindings following kernel dt-bindings
Documentation/devicetree/bindings/mtd/stm32-quadspi.txt
from kernel v4.17-rc1.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
1 file changed