i965: Pass devinfo pointer to is_3src() helpers.

i965: Pass devinfo pointer to is_3src() helpers.

This is not strictly required for the following changes because none
of the three-source opcodes we support at the moment in the compiler
back-end has been removed or redefined, but that's likely to change in
the future.  In any case having hardware instructions specified as a
pair of hardware device and opcode number explicitly in all cases will
simplify the opcode look-up interface introduced in a subsequent
commit, since the opcode number alone is in general ambiguous.

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>