i2c: bcm2835: Add full name of devicetree node to adapter name

Inspired by Lori Hikichi's patch for iproc, this adds the full name of
the devicetree node to the adapter name. With the introduction of
BCM2711 it's very difficult to distinguish between the multiple instances.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>