mm: rename page trylock

mm: rename page trylock

Converting page lock to new locking bitops requires a change of page flag
operation naming, so we might as well convert it to something nicer
(!TestSetPageLocked_Lock => trylock_page, SetPageLocked => set_page_locked).

This also facilitates lockdeping of page lock.

Signed-off-by: Nick Piggin <[email protected]>
Acked-by: KOSAKI Motohiro <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andrew Morton <[email protected]>
Acked-by: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>