nfp: bpf: don't use instruction number for jump target

Instruction number is meaningless at code gen phase.  The target
of the instruction is overwritten by nfp_fixup_branches().  The
convention is to put the raw offset in target address as a place
holder.  See cmp_* functions.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>