Masahiro Yamada authored Aug 12, 2016 and Tom Rini committed Aug 12, 2016

Linux stopped the use of keyword 'boolean' in Kconfig.

Refer to commit 6341e62b212a2541efb0160c470e90bd226d5496 ("kconfig:
use bool instead of boolean for type definition attributes")
in Linux Kernel.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>