i965: Set compute shader shared memory max to 64k

i965: Set compute shader shared memory max to 64k

See Ivy Bridge PRM, Volume 2, Part 2, 1.8.4 INTERFACE_DESCRIPTOR_DATA:

DWORD 5, bits 20:16: "This field indicates how much shared local
memory the thread group requires. The amount is specified in 4k
blocks, but only powers of 2 are allowed: 0, 4k, 8k, 16k, 32k and 64k
per half-slice."

For Haswell, see Volume 2d, INTERFACE_DESCRIPTOR_DATA:

DWORD 5, bits 20:16: With text identical to the Ivy Bridge PRM.

For Broadwell, see Volume 2d, INTERFACE_DESCRIPTOR_DATA:

DWORD 6, bits 20:16: With text identical to the Ivy Bridge PRM.

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Ben Widawsky <benjamin.widawsky@intel.com>