[flang][CUDA] Downgrade error to warning (#161570)

The compiler currently emit an error about the lack of an explicit
procedure interface when an external procedure that is called via an
implicit interface is known to have an dummy argument with a CUDA data
attribute, even when the corresponding actual argument does have a CUDA
data attribute. This behavior is inconsistent with what happens when
such a call is to an external in another source file and its definition
is not visible -- the compiler silently accepts an actual argument with
a CUDA data attribute across the implicit interface.

Harmonize this situation so that an actual argument with a CUDA data
attribute in a reference to a procedure with an implicit interface
elicits a usage warning encouraging the use of explicit interfaces. Only
when the procedure's definition is visible, and incompatible, will an
error message appear.

0 files changed, 0 insertions, 0 deletions