[NVPTX] Fix debugging information being added to NVPTX target if remarks are enabled

Summary:
Optimized debugging is not supported by ptxas. Debugging information is degraded to line information only if optimizations are enabled, but debugging information would be added back in by the driver if remarks were enabled. This solves https://bugs.llvm.org/show_bug.cgi?id=48153.

Reviewers: jdoerfert tra jholewinski serge-sans-paille

Differential Revision: https://reviews.llvm.org/D94123