[flang] Accept non-interoperable LOGICAL scalar dummy arguments

Some Fortran compilers allow kinds of LOGICAL other than C_BOOL
for the types of dummy arguments to interoperable (BIND(C))
procedures.  As any kind of LOGICAL can be converted to any
other without loss of information, this seems to be a useful
unambiguous extension that is attested in real codes; accept it
for scalars with a portability warning.

Differential Revision: https://reviews.llvm.org/D145968