locking/atomic/x86: Redeclare x86_32 arch_atomic64_{add,sub}() as void

Correct the return type of x86_32 arch_atomic64_add() and
arch_atomic64_sub() functions to 'void' and remove redundant return.

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/20240605181424.3228-2-ubizjak@gmail.com

Author: ubizjak

arch/x86/include/asm/atomic64_32.h

@@ -163,20 +163,18 @@ static __always_inline s64 arch_atomic64_dec_return(atomic64_t *v)
 }
 #define arch_atomic64_dec_return arch_atomic64_dec_return
 
-static __always_inline s64 arch_atomic64_add(s64 i, atomic64_t *v)
+static __always_inline void arch_atomic64_add(s64 i, atomic64_t *v)
 {
 	__alternative_atomic64(add, add_return,
 			       ASM_OUTPUT2("+A" (i), "+c" (v)),
 			       ASM_NO_INPUT_CLOBBER("memory"));
-	return i;
 }
 
-static __always_inline s64 arch_atomic64_sub(s64 i, atomic64_t *v)
+static __always_inline void arch_atomic64_sub(s64 i, atomic64_t *v)
 {
 	__alternative_atomic64(sub, sub_return,
 			       ASM_OUTPUT2("+A" (i), "+c" (v)),
 			       ASM_NO_INPUT_CLOBBER("memory"));
-	return i;
 }
 
 static __always_inline void arch_atomic64_inc(atomic64_t *v)