ARM: imx31: Retrieve the IIM base address from devicetree

[ Upstream commit 3172225d45bd918a5c4865e7cd8eb0c9d79f8530 ]

Now that imx31 has been converted to a devicetree-only platform,
retrieve the IIM base address from devicetree.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Stable-dep-of: 87b30c4b0efb ("ARM: imx: add missing of_node_put()")
Signed-off-by: Sasha Levin <sashal@kernel.org>