boot-common.c checks to see if I2C is enabled in SPL, but
it doens't check for DM_I2C before initializing it. This
will now only initialize the I2C is the DM_I2C is not enabled
to avoid initializing it more than once.
Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>