dts: bindings: flash_controller stm32 qspi has requires-ulbpr property

Add the <requires-ulbpr> property from the "jedec,spi-nor-common.yaml"
to the existing st,stm32-qspi-nor.yaml. So that external quad-NOR with
unlock the Global Block Protection (BPR) (opcode 0x98) is accepted.

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