MIPS: JZ4740: Add base support for Ingenic JZ4740 System-on-a-Chip

Adds a new cpu type for the JZ4740 to the Linux MIPS architecture code.
It also adds the iomem addresses for the different components found on
a JZ4740 SoC.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1464/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>