CONFIG_TOSHIBA_RBTX4938_MPLEX_ATA is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

ATA

configname: CONFIG_TOSHIBA_RBTX4938_MPLEX_ATA

PIO[58:61]
└─>ATA
In linux kernel since version 2.6.15 (release Date: 2006-01-02)