[PATCH] MAINTAINERS: Add mpam.rst to the MPAM DRIVER entry

Documentation/arch/arm64/mpam.rst is not listed under MPAM DRIVER, so
get_maintainer.pl names neither MPAM maintainer on a patch to it.

Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
---

Notes:
    Found this while putting together the recipient list for [1]:
    get_maintainer.pl names neither MPAM maintainer on a patch to mpam.rst.
    
    arch/arm64/kernel/mpam.c, arch/arm64/include/asm/mpam.h and
    drivers/acpi/arm64/mpam.c aren't in this entry either, but that
    didn't look as clear cut, so I've left them out. Happy to respin
    with them added.
    
    [1] https://lore.kernel.org/all/20260903084809.2027326-1-fuad.tabba@linux.dev/ (local)

 MAINTAINERS | 1 +
 1 file changed, 1 insertion(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index fc320b373656f..20a6e70df83c8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS

@@ -18438,6 +18438,7 @@ M:	Ben Horgan <ben.horgan@arm.com>
 R:	Reinette Chatre <reinette.chatre@intel.com>
 R:	Fenghua Yu <fenghuay@nvidia.com>
 S:	Maintained
+F:	Documentation/arch/arm64/mpam.rst
 F:	drivers/resctrl/mpam_*
 F:	drivers/resctrl/test_mpam_*
 F:	include/linux/arm_mpam.h

-- 
2.39.5