We need to use "%#" PRIx64 for u64 values, not "%lx", fixing this build
problem on powerpc 32-bit:

  72    13.69 ubuntu:18.04-x-powerpc        : FAIL powerpc-linux-gnu-gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0
    arch/powerpc/util/machine.c: In function 'arch__symbols__fixup_end':
    arch/powerpc/util/machine.c:23:12: error: format '%lx' expects argument of type 'long unsigned int', but argument 6 has type 'u64 {aka long long unsigned int}' [-Werror=format=]
      pr_debug4("%s sym:%s end:%#lx\n", __func__, p->name, p->end);
                ^
    /git/linux/tools/perf/util/debug.h:18:21: note: in definition of macro 'pr_fmt'
     #define pr_fmt(fmt) fmt
                         ^~~
    /git/linux/tools/perf/util/debug.h:33:29: note: in expansion of macro 'pr_debugN'
     #define pr_debug4(fmt, ...) pr_debugN(4, pr_fmt(fmt), ##__VA_ARGS__)
                                 ^~~~~~~~~
    /git/linux/tools/perf/util/debug.h:33:42: note: in expansion of macro 'pr_fmt'
     #define pr_debug4(fmt, ...) pr_debugN(4, pr_fmt(fmt), ##__VA_ARGS__)
                                              ^~~~~~
    arch/powerpc/util/machine.c:23:2: note: in expansion of macro 'pr_debug4'
      pr_debug4("%s sym:%s end:%#lx\n", __func__, p->name, p->end);
      ^~~~~~~~~
    cc1: all warnings being treated as errors
    /git/linux/tools/build/Makefile.build:139: recipe for target 'util' failed
    make[5]: *** [util] Error 2
    /git/linux/tools/build/Makefile.build:139: recipe for target 'powerpc' failed
    make[4]: *** [powerpc] Error 2
    /git/linux/tools/build/Makefile.build:139: recipe for target 'arch' failed
    make[3]: *** [arch] Error 2
  73    30.47 ubuntu:18.04-x-powerpc64      : Ok   powerpc64-linux-gnu-gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0

Fixes: 557c3ead ("perf powerpc: Fix gap between kernel end and module start")
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>