MAINTAINERS: Drop Mark Gross as maintainer for x86 platform drivers

Mark has not really been active as maintainer for x86 platform drivers
lately, drop Mark from the MAINTAINERS entries for drivers/platform/x86,
drivers/platform/mellanox and drivers/platform/surface.

Cc: Mark Gross <[e-mail]>
Signed-off-by: Hans de Goede <[e-mail]>
Acked-by: Andy Shevchenko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ilpo Järvinen <[e-mail]>

MAINTAINERS

···
 MELLANOX HARDWARE PLATFORM SUPPORT
 M:	Hans de Goede <[e-mail]>
 M:	Ilpo Järvinen <[e-mail]>
-M:	Mark Gross <[e-mail]>
 M:	Vadim Pasternak <[e-mail]>
 L:	[e-mail]
 S:	Supported
···
 MICROSOFT SURFACE HARDWARE PLATFORM SUPPORT
 M:	Hans de Goede <[e-mail]>
 M:	Ilpo Järvinen <[e-mail]>
-M:	Mark Gross <[e-mail]>
 M:	Maximilian Luz <[e-mail]>
 L:	[e-mail]
 S:	Maintained
···
 X86 PLATFORM DRIVERS
 M:	Hans de Goede <[e-mail]>
 M:	Ilpo Järvinen <[e-mail]>
-M:	Mark Gross <[e-mail]>
 L:	[e-mail]
 S:	Maintained
 Q:	https://patchwork.kernel.org/project/platform-driver-x86/list/