i.MX6 Quad/Dual open_vivante_v4 driver updates

Imported Vivante driver from the GCW tree that the etnaviv project references, using their "v4_cleaned" tree. I added FDT support.

My wand boots successfully and reports that the GPU was initialized. I haven't tried the userland side yet to really verify functionality, although I've solicited help from the Wandboard fora. Viz:

[    2.919645] galcore 130000.gpu: Using settings from Flattened Device Tree (FDT).
[    2.927228] galcore 130000.gpu: driver v4.6.6, initializing
[    2.932824] galcore options:
[    2.935728]   irqLine           = 41
[    2.939309]   registerMemBase   = 0x00130000
[    2.943583]   registerMemSize   = 0x00004000
[    2.947868]   irqLine2D         = 42
[    2.951448]   registerMemBase2D = 0x00134000
[    2.955733]   registerMemSize2D = 0x00004000
[    2.960010]   contiguousSize    = 4194304
[    2.964033]   contiguousBase    = 0x00000000
[    2.968308]   bankSize          = 0x02000000
[    2.972583]   fastClear         = -1
[    2.976171]   compression       = -1
[    2.979752]   signal            = 48
[    2.983331]   baseAddress       = 0x00000000
[    2.987614]   physSize          = 0x00000000
[    3.037802] galcore 130000.gpu: GPU initialized, clocked at 594MHz

Signed-off-by: B. Scott Michel <bscottm@ieee.org>
Signed-off-by: Robert Nelson <robertcnelson@gmail.com>