i965: Add gen7+ sampler state to batch debug

i965: Add gen7+ sampler state to batch debug

OLD:
0x00007e00:      0x10000000: WM SAMP0: filtering
0x00007e04:      0x000d0000: WM SAMP0: wrapping, lod
0x00007e08:      0x00000000: WM SAMP0: default color pointer
0x00007e0c:      0x00000090: WM SAMP0: chroma key, aniso

NEW:
0x00007e00:      0x10000000: SAMPLER_STATE 0: Disabled = no, Base Mip: 0.0, Mip/Mag/Min Filter: NONE/NEAREST/NEAREST, LOD Bias: 0.0
0x00007e04:      0x000d0000: SAMPLER_STATE 0: Min LOD: 0.0, Max LOD: 13.0
0x00007e08:      0x00000000: SAMPLER_STATE 0: Border Color
0x00007e0c:      0x00000090: SAMPLER_STATE 0: Max aniso: RATIO 2:1, TC[XYZ] Address Control: CLAMP|CLAMP|WRAP

v2: Move GET_BITS macro to here (with paren protection) Ben/Topi
Add const to the sampler pointer (Topi)

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>