arch: Remove spin_unlock_wait() arch-specific definitions

arch: Remove spin_unlock_wait() arch-specific definitions

There is no agreed-upon definition of spin_unlock_wait()'s semantics,
and it appears that all callers could do just as well with a lock/unlock
pair.  This commit therefore removes the underlying arch-specific
arch_spin_unlock_wait() for all architectures providing them.

Signed-off-by: Paul E. McKenney <[email protected]>
Cc: <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Alan Stern <[email protected]>
Cc: Andrea Parri <[email protected]>
Cc: Linus Torvalds <[email protected]>
Acked-by: Will Deacon <[email protected]>
Acked-by: Boqun Feng <[email protected]>