ARM: mx25: Print silicon revision on boot

ARM: mx25: Print silicon revision on boot

Silicon revision is useful information to have during kernel boot.
Print the MX25 silicon revision.

[ukleinek: squashed in a fix by Jason Liu <jason.hui@linaro.org>
defining MX25_IIM_BASE_ADDR]

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Jason Liu <jason.hui@linaro.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>