CONFIG_MACH_DOCKSTAR is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_MACH_DOCKSTAR.
Result is shown for kernelversion 6.2.5

Seagate FreeAgent DockStar

modulename: dockstar-setup.ko

configname: CONFIG_MACH_DOCKSTAR

Linux Kernel Configuration
└─>Marvell Kirkwood Implementations
└─>Seagate FreeAgent DockStar
In linux kernel since version 2.6.37 (release Date: 2011-01-04)  
Say 'Y' here if you want your kernel to support the
Seagate FreeAgent DockStar.

source code:
arch/arm/mach-kirkwood/dockstar-setup.c