platform/x86/siemens: add missing MODULE_DESCRIPTION() macros

With ARCH=x86, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/platform/x86/siemens/simatic-ipc.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/platform/x86/siemens/simatic-ipc-batt.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/platform/x86/siemens/simatic-ipc-batt-apollolake.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/platform/x86/siemens/simatic-ipc-batt-elkhartlake.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/platform/x86/siemens/simatic-ipc-batt-f7188x.o

Add the missing invocations of the MODULE_DESCRIPTION() macro.

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20240611-md-drivers-platform-x86-siemens-v1-1-b399d7d6ae64@quicinc.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>