ARM: imx3: Fix CCM node reference leak

ARM: imx3: Fix CCM node reference leak

of_find_compatible_node() returns a referenced device node. The i.MX31
and i.MX35 early init paths use the node to map the CCM registers with
of_iomap(), but never drop the node reference.

Release the node after the mapping is created.

Fixes: 2cf98d12958c ("ARM: imx3: Retrieve the CCM base address from devicetree")
Signed-off-by: Yuho Choi <dbgh9129@gmail.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>