arm64: dts: lx2160a-cex7: delete RTC interrupt

The RTC interrupt is incorrect and prevents the RTC driver
initialising. In any case, the PCF2127 driver wants an active low
interrupt, which neither the GIC nor the GPIO blocks support.
There is an ISPPT block in the LX2160A, but this is not supported
in mainline kernels. So, just delete the interrupt.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>