cpuimx27: fix i2c bus selection

Recent clean of i.MX devices registration changed the i2C bus number
selected for our platform (Freescale start peripheral ID at 1, kernel
now start it at 0 so i.MX27's i2c 1 is kernel's i2c 0).
Without this fix, i2c is unusable on this platform.

Signed-off-by: Eric Bénard <eric@eukrea.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>