For scheduling multiple ULSCH ahead, we will have to use different k2.
Hence, we will need to check for k2 in the TDA selection as well. The
function get_ul_tda() is renamed to get_num_ul_tda() to reflect that it
might return multiple TDAs (not done in this commit, but in a follow-up
MR). get_num_ul_tda() also returns a pointer to the first suitable TDA.
In the phy-test scheduler, simplify the selection of the TDA to use: do
not hardcode a specific K2, but rather, use the first one (with any k2).