dts: arm: stm32 reg definition for the st,stm32-qspi compatible

The st,stm32-qspi compatible is defining the reg property
with the register address and size at first index
followed by the external mem base address and max allocated size.
For the stm32F412, stm32F7, stm32L4, stm32H7, stm32WB series.
qspi is addressing max 256 MBytes from 0x90000000.

Signed-off-by: Francois Ramu <francois.ramu@st.com>