Allow mixing subprogs and tail calls by passing the current tail
call count to subprogs.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230129190501.1624747-6-iii@linux.ibm.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>