i965: STATIC_ASSERT that there aren't too many BRW_NEW_* flags.

i965: STATIC_ASSERT that there aren't too many BRW_NEW_* flags.

We are getting close to the maximum number of BRW_NEW_* bits that can
be stored in brw->state.dirty.brw without overflowing 32 bits, and
geometry shaders are going to add more.  Add a STATIC_ASSERT so that
we will be alerted when we need to switch to 64 bits.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>