CUDA component callback subscriber limits usage by other packages

[john.rodgers]

The CUPTI callback subscriber introduced to monitor contexts creates a problem for packages that use PAPI for CUDA HWPC collection. Specifically, it prevents registering of custom profiling/tracing callbacks, resulting in CUPTI_ERROR_MULTIPLE_SUBSCRIBERS_NOT_SUPPORTED when attempting to register one.

Subscriber introduced in commit: https://bitbucket.org/icl/papi/commits/9ff1d73dae9a7b297a54a77fac5fdb3957041452

[Giuseppe Congiu]

Resolved by PR #282 https://bitbucket.org/icl/papi/pull-requests/282