dt-bindings: mtd: fsl-quadspi: Pass the qspi clock names

In order to improve the bindings documentation, explicitly pass the name
of the clocks: "qspi_en" and "qspi", which are mandatory.
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NCyrille Pitchen <cyrille.pitchen@wedev4u.fr>

Documentation/devicetree/bindings/mtd/fsl-quadspi.txt

@@ -12,7 +12,7 @@ Required properties:
   - reg-names: Should contain the reg names "QuadSPI" and "QuadSPI-memory"
   - interrupts : Should contain the interrupt for the device
   - clocks : The clocks needed by the QuadSPI controller
-  - clock-names : the name of the clocks
+  - clock-names : Should contain the name of the clocks: "qspi_en" and "qspi".
 
 Optional properties:
   - fsl,qspi-has-second-chip: The controller has two buses, bus A and bus B.