perf symbols: Fix unaligned access in get_x86_64_plt_disp()

Use memcpy() to avoid unaligned access.

Discovered using EXTRA_CFLAGS="-fsanitize=undefined -fsanitize=address".

Fixes: ce4c8e79 ("perf symbols: Get symbols for .plt.got for x86-64")
Reported-by: kernel test robot <yujie.liu@intel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/oe-lkp/202303061424.6ad43294-yujie.liu@intel.com
Link: https://lore.kernel.org/r/20230316194156.8320-2-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/symbol-elf.c

@@ -542,9 +542,12 @@ static u32 get_x86_64_plt_disp(const u8 *p)
 		n += 1;
 	/* jmp with 4-byte displacement */
 	if (p[n] == 0xff && p[n + 1] == 0x25) {
+		u32 disp;
+
 		n += 2;
 		/* Also add offset from start of entry to end of instruction */
-		return n + 4 + le32toh(*(const u32 *)(p + n));
+		memcpy(&disp, p + n, sizeof(disp));
+		return n + 4 + le32toh(disp);
 	}
 	return 0;
 }