ARM: mx5/mm: consolidate TZIC map code

Use a static mapping for TZIC to get rid of the duplicated code for
ioremap and the corresponding error handling. This is already done on
i.MX50.

This patch also removes TZIC mapping for i.mx51 TO1 since
there is no support for TO1 now since the following commit:
9ab4650 (ARM: imx: Get the silicon version from the IIM module)

Signed-off-by: Jason Liu <jason.hui@linaro.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>