locking/atomic/x86: Define arch_atomic_sub() family using arch_atomic_add() functions

There is no need to implement arch_atomic_sub() family of inline
functions, corresponding macros can be directly implemented using
arch_atomic_add() inlines with negated argument.

No functional changes intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240410062957.322614-4-ubizjak@gmail.com