Use "pulongest" on aarch64-tdep.c:aarch64_gdbarch_init

Use "pulongest" on aarch64-tdep.c:aarch64_gdbarch_init

While trying to build GDB on i686, I found the following error:

 In file included from ../../gdb/common/common-defs.h:105,
                  from ../../gdb/defs.h:28,
                  from ../../gdb/aarch64-tdep.c:21:
 ../../gdb/aarch64-tdep.c: In function 'gdbarch* aarch64_gdbarch_init(gdbarch_info, gdbarch_list*)':
 ../../gdb/aarch64-tdep.c:3176:43: error: format '%ld' expects argument of type 'long int', but argument 4 has type 'uint64_t' {aka 'long long unsigned int'} [-Werror=format=]
  3176 |     internal_error (__FILE__, __LINE__, _("VQ out of bounds: %ld (max %d)"),
       |                                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 ../../gdb/common/gdb_locale.h:28:29: note: in definition of macro '_'
    28 | # define _(String) gettext (String)
       |                             ^~~~~~
 ../../gdb/aarch64-tdep.c:3176:64: note: format string is defined here
  3176 |     internal_error (__FILE__, __LINE__, _("VQ out of bounds: %ld (max %d)"),
       |                                                              ~~^
       |                                                                |
       |                                                                long int
       |                                                              %lld

This happens because aarch64-tdep.c:aarch64_gdbarch_init prints a
"uint64_t" variable using "%ld".  This patch fixes the build by using
"pulongest" instead.  As explained in a similar fix (commit
495143533ad95369811391c6e3c6dadd69d7dd67), this should be safe because
if aarch64-tdep.c is included in the build, then ULONGEST must be a
64-bit type.

gdb/ChangeLog:
2019-04-24  Sergio Durigan Junior  <sergiodj@redhat.com>

	* aarch64-tdep.c (aarch64_gdbarch_init): Use "pulongest" to print
	"vq".