[PATCH] perf: arm64: Fix compilation error

[Leo Yan <leo.yan@arm.com>]

Since the commit dc6d2bc2d893 ("perf sample: Make user_regs and
intr_regs optional"), the building for Arm64 reports error:

arch/arm64/util/unwind-libdw.c: In function ‘libdw__arch_set_initial_registers’:
arch/arm64/util/unwind-libdw.c:11:32: error: initialization of ‘struct regs_dump *’ from incompatible pointer type ‘struct regs_dump **’ [-Werror=incompatible-pointer-types]
   11 |  struct regs_dump *user_regs = &ui->sample->user_regs;
      |                                ^
cc1: all warnings being treated as errors
make[6]: *** [/home/niayan01/linux/tools/build/Makefile.build:85: arch/arm64/util/unwind-libdw.o] Error 1
make[5]: *** [/home/niayan01/linux/tools/build/Makefile.build:138: util] Error 2
arch/arm64/tests/dwarf-unwind.c: In function ‘test__arch_unwind_sample’:
arch/arm64/tests/dwarf-unwind.c:48:27: error: initialization of ‘struct regs_dump *’ from incompatible pointer type ‘struct regs_dump **’ [-Werror=incompatible-pointer-types]
   48 |  struct regs_dump *regs = &sample->user_regs;
      |                           ^

To fix the issue, use the helper perf_sample__user_regs() to retrieve
the user_regs.

Fixes: dc6d2bc2d893 ("perf sample: Make user_regs and intr_regs optional")
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
 tools/perf/arch/arm64/tests/dwarf-unwind.c | 2 +-
 tools/perf/arch/arm64/util/unwind-libdw.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/arch/arm64/tests/dwarf-unwind.c b/tools/perf/arch/arm64/tests/dwarf-unwind.c
index b2603d0d3737..440d00f0de14 100644
--- a/tools/perf/arch/arm64/tests/dwarf-unwind.c
+++ b/tools/perf/arch/arm64/tests/dwarf-unwind.c
@@ -45,7 +45,7 @@ static int sample_ustack(struct perf_sample *sample,
 int test__arch_unwind_sample(struct perf_sample *sample,
 		struct thread *thread)
 {
-	struct regs_dump *regs = &sample->user_regs;
+	struct regs_dump *regs = perf_sample__user_regs(sample);
 	u64 *buf;
 
 	buf = calloc(1, sizeof(u64) * PERF_REGS_MAX);
diff --git a/tools/perf/arch/arm64/util/unwind-libdw.c b/tools/perf/arch/arm64/util/unwind-libdw.c
index e056d50ab42e..b89b0a7e5ad9 100644
--- a/tools/perf/arch/arm64/util/unwind-libdw.c
+++ b/tools/perf/arch/arm64/util/unwind-libdw.c
@@ -8,7 +8,7 @@
 bool libdw__arch_set_initial_registers(Dwfl_Thread *thread, void *arg)
 {
 	struct unwind_info *ui = arg;
-	struct regs_dump *user_regs = &ui->sample->user_regs;
+	struct regs_dump *user_regs = perf_sample__user_regs(ui->sample);
 	Dwarf_Word dwarf_regs[PERF_REG_ARM64_MAX], dwarf_pc;
 
 #define REG(r) ({						\
-- 
2.34.1