xen/efi: Set nonblocking callbacks

Other parts of the kernel expect these nonblocking EFI callbacks to
exist and crash when running under Xen. Since the implementations of
xen_efi_set_variable() and xen_efi_query_variable_info() do not take any
locks, use them for the nonblocking callbacks too.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

arch/x86/xen/efi.c

@@ -65,7 +65,9 @@ static efi_system_table_t __init *xen_efi_probe(void)
 	efi.get_variable             = xen_efi_get_variable;
 	efi.get_next_variable        = xen_efi_get_next_variable;
 	efi.set_variable             = xen_efi_set_variable;
+	efi.set_variable_nonblocking = xen_efi_set_variable;
 	efi.query_variable_info      = xen_efi_query_variable_info;
+	efi.query_variable_info_nonblocking = xen_efi_query_variable_info;
 	efi.update_capsule           = xen_efi_update_capsule;
 	efi.query_capsule_caps       = xen_efi_query_capsule_caps;
 	efi.get_next_high_mono_count = xen_efi_get_next_high_mono_count;