media: cx231xx: Fix recursive dependency

0day build bot reported an unnoticed recursive dependency, fix it
by removing the select statement.

fixes: c66d4d99a8fb ("cx231xx: Add I2C_MUX dependency")
Signed-off-by: Brad Love <brad@nextdimension.cc>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/usb/cx231xx/Kconfig

@@ -6,7 +6,6 @@ config VIDEO_CX231XX
 	select VIDEOBUF_VMALLOC
 	select VIDEO_CX25840
 	select VIDEO_CX2341X
-	select I2C_MUX
 
 	---help---
 	  This is a video4linux driver for Conexant 231xx USB based TV cards.