Implement glScissor support
Created by: PabloPL
It's mostly done on https://github.com/yuq/mesa-lima/pull/10. There is only one case to handle - when scissors = (0,0,0,0)
- Limadriver in this case is not doing any scissors and displaying full/normal image (probably a bug)
- Mali binary driver is generating only following plbu commands (dump from egl_quad_flat from limadrver tests)
0x00000200 0x1000010b // PRIMITIVE_SETUP
0x00010000 0x1000010c // BLOCK_STEP
0x1d001d00 0x10000109 // TILED_DIMENSIONS
0x0000001e 0x30000000 // BLOCK_STRIDE
0x400f8400 0x280001c1 // ARRAY_ADDRESS
0x00000000 0x10000107 // VIEWPORT_X
0x43f00000 0x10000108 // VIEWPORT_W
0x00000000 0x10000105 // VIEWPORT_Y
0x43f00000 0x10000106 // VIEWPORT_H
0x40040000 0x10000103 // TILE_HEAP_START
0x40070000 0x10000104 // TILE_HEAP_END
0x00000000 0x50000000 // END