'def_tristate' is a shorthand for 'default' + 'tristate'.

Another 'tristate' is redundant.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20240215135304.1909431-1-masahiroy@kernel.orgSigned-off-by: Takashi Iwai <tiwai@suse.de>