MAINTAINERS: Add reviewers for fs/resctrl

resctrl has existed for quite a while as a filesystem interface private to
arch/x86. To allow other architectures to support the same user interface
for similar hardware features, it has been moved to /fs/.

Add those with a vested interest in the common code as reviewers.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Acked-by: Dave Martin <Dave.Martin@arm.com>
Tested-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/20250515165855.31452-26-james.morse@arm.com