riscv: atomic: Cleanup unnecessary definition

The cmpxchg32 & cmpxchg32_local are not used in Linux anymore. So
clean up asm/cmpxchg.h.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20220505035526.2974382-2-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Author: guoren83

arch/riscv/include/asm/cmpxchg.h

@@ -348,18 +348,6 @@
 #define arch_cmpxchg_local(ptr, o, n)					\
 	(__cmpxchg_relaxed((ptr), (o), (n), sizeof(*(ptr))))
 
-#define cmpxchg32(ptr, o, n)						\
-({									\
-	BUILD_BUG_ON(sizeof(*(ptr)) != 4);				\
-	arch_cmpxchg((ptr), (o), (n));					\
-})
-
-#define cmpxchg32_local(ptr, o, n)					\
-({									\
-	BUILD_BUG_ON(sizeof(*(ptr)) != 4);				\
-	arch_cmpxchg_relaxed((ptr), (o), (n))				\
-})
-
 #define arch_cmpxchg64(ptr, o, n)					\
 ({									\
 	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\