etnaviv: Generate new sin/cos instructions on GC3000

etnaviv: Generate new sin/cos instructions on GC3000

Shaders using sin/cos instructions were not working on GC3000.

The reason for this turns out to be that these chips implement sin/cos
in a different way (but using the same opcodes):

- Need their input scaled by 1/pi instead of 2/pi.

- Output an x and y component, which need to be multiplied to
  get the result.

- tex_amode needs to be set to 1.

Add a new bit to the compiler specs and generate these instructions
as necessary.

CC: <mesa-stable@lists.freedesktop.org>
Signed-off-by: Wladimir J. van der Laan <laanwj@gmail.com>
Acked-by: Christian Gmeiner <christian.gmeiner@gmail.com>