powerpc/atomics: Remove unused function

Remove arch_atomic_try_cmpxchg_lock function as it is no longer used
since commit 9f61521c ("powerpc/qspinlock: powerpc qspinlock
implementation")
Signed-off-by: Nysal Jan K.A <nysal@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230224103940.1328725-1-nysal@linux.ibm.com

arch/powerpc/include/asm/atomic.h

@@ -130,35 +130,6 @@ ATOMIC_OPS(xor, xor, "", K)
 #define arch_atomic_xchg_relaxed(v, new) \
 	arch_xchg_relaxed(&((v)->counter), (new))
 
-/*
- * Don't want to override the generic atomic_try_cmpxchg_acquire, because
- * we add a lock hint to the lwarx, which may not be wanted for the
- * _acquire case (and is not used by the other _acquire variants so it
- * would be a surprise).
- */
-static __always_inline bool
-arch_atomic_try_cmpxchg_lock(atomic_t *v, int *old, int new)
-{
-	int r, o = *old;
-	unsigned int eh = IS_ENABLED(CONFIG_PPC64);
-
-	__asm__ __volatile__ (
-"1:	lwarx	%0,0,%2,%[eh]	# atomic_try_cmpxchg_acquire		\n"
-"	cmpw	0,%0,%3							\n"
-"	bne-	2f							\n"
-"	stwcx.	%4,0,%2							\n"
-"	bne-	1b							\n"
-"\t"	PPC_ACQUIRE_BARRIER "						\n"
-"2:									\n"
-	: "=&r" (r), "+m" (v->counter)
-	: "r" (&v->counter), "r" (o), "r" (new), [eh] "n" (eh)
-	: "cr0", "memory");
-
-	if (unlikely(r != o))
-		*old = r;
-	return likely(r == o);
-}
-
 /**
  * atomic_fetch_add_unless - add unless the number is a given value
  * @v: pointer of type atomic_t