MIPS: AR7: Add support for Titan (TNETV10xx) SoC variant

Add support for Titan TNETV1050,1055,1056,1060 variants. This SoC is almost
completely identical to AR7 except on a few points:
- a second bank of gpios is available
- vlynq0 on titan is vlynq1 on ar7
- different PHY addresses for cpmac0

This SoC can be found on commercial products like the Linksys WRTP54G

Original patch by Xin with improvments by Florian.

Signed-off-by: Xin Zhen <xlonestar2000@aim.com>
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/1563/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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