[PATCHv2] powerpc/lib/sstep: fix 'ptesync' build error

[Anders Roxell <anders.roxell@linaro.org>]

Building tinyconfig with gcc (Debian 11.2.0-16) and assembler (Debian
2.37.90.20220207) the following build error shows up:

{standard input}: Assembler messages:
{standard input}:2088: Error: unrecognized opcode: `ptesync'
make[3]: *** [/builds/linux/scripts/Makefile.build:287: arch/powerpc/lib/sstep.o] Error 1

Add the 'ifdef CONFIG_PPC64' around the 'ptesync' in function
'emulate_update_regs()' to like it is in 'analyse_instr()'. Since it looks like
it got dropped inadvertently by commit 3cdfcbfd32b9 ("powerpc: Change
analyse_instr so it doesn't modify *regs").

Cc: stable@vger.kernel.org # v4.14+
Fixes: 3cdfcbfd32b9 ("powerpc: Change analyse_instr so it doesn't modify *regs")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
---
 arch/powerpc/lib/sstep.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index a94b0cd0bdc5..bd3734d5be89 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -3264,12 +3264,14 @@ void emulate_update_regs(struct pt_regs *regs, struct instruction_op *op)
 		case BARRIER_EIEIO:
 			eieio();
 			break;
+#ifdef CONFIG_PPC64
 		case BARRIER_LWSYNC:
 			asm volatile("lwsync" : : : "memory");
 			break;
 		case BARRIER_PTESYNC:
 			asm volatile("ptesync" : : : "memory");
 			break;
+#endif
 		}
 		break;
 
-- 
2.34.1