sched: Move STDL_INIT() functions out-of-line

Since all these functions are address-taken in SDTL_INIT() and called
indirectly, it doesn't really make sense for them to be inline.

Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>