[mlir] Remove loop peeling explicit C'tor (#175419)
The SCF dialect loop peeling pass has an explicit C'tor. This creates an
inconvenience to use non default pass options, since they can only be
passed as a string after the pass creation. After removing the explicit
C'tor, the code auto generation creates 2 C'tors, which one of them can
directly receive pass options struct in case non default values are
required.
The explicit C'tor does not match auto generated C'tor convention, so
this change requires any uses of the pass in downstream projects to
update to use the auto generated C'tor.
