access: dtv: fix compilation error on enumerated type

In file included from ../../modules/access/dtv/access.c:27:
../../modules/access/dtv/access.c: In function ‘GetSingleDelivery’:
../../modules/access/dtv/access.c:922:21: error: argument 1 in call to function ‘__builtin_stdc_trailing_zeros’ has enumerated type
  922 |         return 1 << stdc_trailing_zeros(d);
      |                     ^~~~~~~~~~~~~~~~~~~
../../modules/access/dtv/access.c:923:1: warning: control reaches end of non-void function [-Wreturn-type]
  923 | }
      | ^