ARM: dts: NSP: Fix i2c controller interrupt type

The i2c controller should use IRQ_TYPE_LEVEL_HIGH instead of
IRQ_TYPE_NONE.

Fixes: 0f9f27a3

 ("ARM: dts: NSP: Add I2C support to the DT")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>