CONFIG_MIPS_ALCHEMY is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

Alchemy processor based machines

modulename: pci-alchemy.ko

configname: CONFIG_MIPS_ALCHEMY

System type
└─>Alchemy processor based machines
In linux kernel since version 2.6.36 (release Date: 2010-10-20)  
source code:
arch/mips/pci/pci-alchemy.c

is selected by
CONFIG_SND_AU1X00