CONFIG_HD6446X_SERIES is not available for thedefaultarchitecture x86.
Result is shown for architecture sh

CONFIG_HD6446X_SERIES (not configurable)

configname: CONFIG_HD6446X_SERIES

Linux Kernel Configuration
└─>Companion Chips
└─>HD6446X_SERIES
In linux kernel since version 2.6.12  
is depended by
CONFIG_SH_HP6XX