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

Maple Bus support

modulename: maple.ko

configname: CONFIG_MAPLE

Linux Kernel Configuration
└─>Bus options
└─>Maple Bus support
In linux kernel since version 2.6.12  
The Maple Bus is SEGA's serial communication bus for peripherals
on the Dreamcast. Without this bus support you won't be able to
get your Dreamcast keyboard etc to work, so most users
probably want to say 'Y' here, unless you are only using the
Dreamcast with a serial line terminal or a remote network
connection.

source code: