perf: Register PMU implementations

perf: Register PMU implementations

Simple registration interface for struct pmu, this provides the
infrastructure for removing all the weak functions.

Signed-off-by: Peter Zijlstra <[email protected]>
Cc: paulus <[email protected]>
Cc: stephane eranian <[email protected]>
Cc: Robert Richter <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Paul Mundt <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Cyrill Gorcunov <[email protected]>
Cc: Lin Ming <[email protected]>
Cc: Yanmin <[email protected]>
Cc: Deng-Cheng Zhu <[email protected]>
Cc: David Miller <[email protected]>
Cc: Michael Cree <[email protected]>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <[email protected]>