Allow @RequiresPermission to be specified on parameters

This allows you to express that the permission requirement
on a method depends on a given parameter; static analysis
tools should then trace the supplied value backwards to
see whether it points to a constant which in turn has been
annotated with @RequiresPermission.

Change-Id: Ifaf3c2517a2c416b00409d646d6ec881c6b7af18