dt-bindings: i2c: iproc: add "brcm, iproc-nic-i2c" compatible string

Update iProc I2C binding document to add new compatible string
"brcm,iproc-nic-i2c". Optional property "brcm,ape-hsls-addr-mask" is
also added that allows configuration of the host view into the APE's
address for "brcm,iproc-nic-i2c"

Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
Signed-off-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>