xen/pvh: Annotate data appropriately

Use the new SYM_DATA_START_LOCAL, and SYM_DATA_END* macros to get:

  0000     8 OBJECT  LOCAL  DEFAULT    6 gdt
  0008    32 OBJECT  LOCAL  DEFAULT    6 gdt_start
  0028     0 OBJECT  LOCAL  DEFAULT    6 gdt_end
  0028   256 OBJECT  LOCAL  DEFAULT    6 early_stack
  0128     0 OBJECT  LOCAL  DEFAULT    6 early_stack

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Andy Shevchenko <andy@infradead.org>
Cc: Darren Hart <dvhart@infradead.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: linux-arch@vger.kernel.org
Cc: platform-driver-x86@vger.kernel.org
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20191011115108.12392-15-jslaby@suse.cz