x86/EFI: permit setting variable with non-zero attributes

This must have been a copy-and-paste mistake - get_variable uses
op->misc as output only, and wants to make sure it's zero for future
extensibility. For set_variable, this is an input though, and hence
the check is wrong.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/efi/runtime.c
+++ b/xen/arch/x86/efi/runtime.c
@@ -398,9 +398,6 @@ int efi_runtime_call(struct xenpf_efi_ru
         long len;
         unsigned char *data;
 
-        if ( op->misc )
-            return -EINVAL;
-
         len = gwstrlen(guest_handle_cast(op->u.set_variable.name, CHAR16));
         if ( len < 0 )
             return len;