perf: Extend the bit width of the arch-specific flag

The auto counter reload feature requires an event flag to indicate an
auto counter reload group, which can only be scheduled on specific
counters that enumerated in CPUID. However, the hw_perf_event.flags has
run out on X86.

Two solutions were considered to address the issue.
- Currently, 20 bits are reserved for the architecture-specific flags.
  Only the bit 31 is used for the generic flag. There is still plenty
  of space left. Reserve 8 more bits for the arch-specific flags.
- Add a new X86 specific hw_perf_event.flags1 to support more flags.

The former is implemented. Enough room is still left in the global
generic flag.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Thomas Falcon <thomas.falcon@intel.com>
Link: https://lkml.kernel.org/r/20250327195217.2683619-4-kan.liang@linux.intel.com

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