ARM: dts: dra7-evm: remove interrupt binding

The qspi node defines crossbar number as its interrupt number. But,
the crossbar dts patches are not yet there, this causes a warning during
boot.  So interrupts = < > property should be removed from DT and added
later by crossbar series.

Reported-by: Sricharan R <r.sricharan@ti.com>
Signed-off-by: Sourav Poddar <sourav.poddar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>