perf/x86/intel/uncore: Support customized MMIO map size

For a server platform, the MMIO map size is always 0x4000. However, a
client platform may have a smaller map size.

Make the map size customizable.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Link: https://lore.kernel.org/r/20250707201750.616527-3-kan.liang@linux.intel.com