The imx25 chip provides 3 i2c buses, but they have all been named
"i2c", which makes it difficult to predict which bus a device will
be connected to when specified on the command line.

This patch addresses the issue by naming the buses uniquely:
  i2c-bus.0 i2c-bus.1 i2c-bus.2

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Message-id: 20170105043430.3176-2-alastair@au1.ibm.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>