dt-bindings: touchscreen: edt-ft5x06: Remove unneeded I2C unit name

The following warnings are seen with 'make dt_binding_check':

Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.example.dts:19.22-30.11: Warning (unit_address_vs_reg): /example-0/i2c@00000000: node has a unit name, but no reg or ranges property
Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.example.dts:19.22-30.11: Warning (unit_address_format): /example-0/i2c@00000000: unit name should not have leading 0s

Fix it by removing the unneeded i2c unit name.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>