default or selected kernelversion does not have config value CONFIG_LIBERTAS_CS.
Result is shown for kernelversion 6.9.9

Marvell Libertas 8385 CompactFlash 802.11b/g cards

modulename: libertas_cs.ko

configname: CONFIG_LIBERTAS_CS

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Wireless LAN
└─>Marvell Libertas 8385 CompactFlash 802.11b/g cards
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
A driver for Marvell Libertas 8385 CompactFlash devices.

source code:
drivers/net/wireless/marvell/libertas/