crash: export paddr_vmcoreinfo_note()

The following patch is going to use the symbol from the fw_cfg module,
to call the function and write the note location details in the
vmcoreinfo entry, so qemu can produce dumps with the vmcoreinfo note.

CC: Andrew Morton <akpm@linux-foundation.org>
CC: Hari Bathini <hbathini@linux.vnet.ibm.com>
CC: Tony Luck <tony.luck@intel.com>
CC: Vivek Goyal <vgoyal@redhat.com>
Acked-by: NBaoquan He <bhe@redhat.com>
Acked-by: NDave Young <dyoung@redhat.com>
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: NGabriel Somlo <somlo@cmu.edu>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

kernel/crash_core.c

@@ -376,6 +376,7 @@ phys_addr_t __weak paddr_vmcoreinfo_note(void)
 {
 	return __pa(vmcoreinfo_note);
 }
+EXPORT_SYMBOL(paddr_vmcoreinfo_note);
 
 static int __init crash_save_vmcoreinfo_init(void)
 {