i965/nir: Resolve source modifiers on Gen8+ logic operations.

i965/nir: Resolve source modifiers on Gen8+ logic operations.

On Gen8+, AND/OR/XOR/NOT don't support the abs() source modifier, and
negate changes meaning to bitwise-not (~, not -).  This isn't what NIR
expects, so we should resolve the source modifers via a MOV.

+30 Piglits (fs-op-bit{and,or,xor}-not-abs-*).

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>