MAINTAINERS: Add documentation reference for Mellanox platform

Add reference for Documentation/ABI/stable/sysfs-driver-mlxreg-io
under "MELLANOX HARDWARE PLATFORM SUPPORT".

Signed-off-by: Vadim Pasternak <[email protected]>
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Ilpo Järvinen <[email protected]>
Signed-off-by: Ilpo Järvinen <[email protected]>

Author: vadimp-nvidia

MAINTAINERS

@@ -15030,6 +15030,7 @@ M:	Ilpo Järvinen <[email protected]>
 M:	Vadim Pasternak <[email protected]>
 L:	[email protected]
 S:	Supported
+F:	Documentation/ABI/stable/sysfs-driver-mlxreg-io
 F:	Documentation/ABI/testing/sysfs-platform-mellanox-bootctl
 F:	drivers/platform/mellanox/
 F:	include/linux/platform_data/mlxreg.h