x86/resctrl: Fix types in resctrl_arch_mon_ctx_{alloc,free}() stubs

resctrl_arch_mon_ctx_alloc() and resctrl_arch_mon_ctx_free() take an enum
resctrl_event_id that is already defined in resctrl_types.h to be
accessible to asm/resctrl.h.

The x86 stubs take an int. Fix that.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/20250515165855.31452-19-james.morse@arm.com