lisa/_assets/kmodules/sched_tp/Makefile: Do not use pahole --forward_decl

FIX

--forward_decl dumps the forward declaration of every type in the
kernel. Unfortunately, some android kernels redefine the same type
multiple times (struct map_info/union map_info) leading to an invalid
header.

Instead of using this pahole option, use sed to generate the
declarations of just the types used in the header.