powerpc/pmem: Avoid the barrier in flush routines

nvdimm expect the flush routines to just mark the cache clean. The barrier
that mark the store globally visible is done in nvdimm_flush().
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200701072235.223558-7-aneesh.kumar@linux.ibm.com

arch/powerpc/lib/pmem.c

@@ -19,9 +19,6 @@ static inline void __clean_pmem_range(unsigned long start, unsigned long stop)
 
 	for (i = 0; i < size >> shift; i++, addr += bytes)
 		asm volatile(PPC_DCBSTPS(%0, %1): :"i"(0), "r"(addr): "memory");
-
-
-	asm volatile(PPC_PHWSYNC ::: "memory");
 }
 
 static inline void __flush_pmem_range(unsigned long start, unsigned long stop)
@@ -34,9 +31,6 @@ static inline void __flush_pmem_range(unsigned long start, unsigned long stop)
 
 	for (i = 0; i < size >> shift; i++, addr += bytes)
 		asm volatile(PPC_DCBFPS(%0, %1): :"i"(0), "r"(addr): "memory");
-
-
-	asm volatile(PPC_PHWSYNC ::: "memory");
 }
 
 static inline void clean_pmem_range(unsigned long start, unsigned long stop)