doc: device-tree-bindings: alignment with v5.2-rc6 for spi-stm32-qspi.txt

Align doc/device-tree-bindings/spi/spi-stm32-qspi.txt with kernel v5.2-rc6

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
1 file changed