media: stk1160: Simplify the build config definition

Commit dfb9f94e ("[media] stk1160: Build as a module if SND is m and
audio support is selected") had to introduce some complex config dependency
handling to compile for all combinations of configs VIDEO_STK1160 and
VIDEO_STK1160_AC97.

Later, commit e36e6b5f ("[media] stk1160: Remove stk1160-mixer and
setup internal AC97 codec automatically") removes the config
VIDEO_STK1160_AC97, which renders the previous dependency handling
unnecessary. The commit already simplified the dependency of the remaining
config VIDEO_STK1160, but it misses the opportunity to merge VIDEO_STK1160
and VIDEO_STK1160_COMMON.

So, do that now and simplify the build config definition of the STK1160 USB
video capture support.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/usb/stk1160/Kconfig

 # SPDX-License-Identifier: GPL-2.0-only
-config VIDEO_STK1160_COMMON
+config VIDEO_STK1160
 	tristate "STK1160 USB video capture support"
 	depends on VIDEO_DEV && I2C
-
+	select VIDEOBUF2_VMALLOC
+	select VIDEO_SAA711X
 	help
 	  This is a video4linux driver for STK1160 based video capture devices.
 
@@ -12,10 +13,3 @@ config VIDEO_STK1160_COMMON
 	  This driver only provides support for video capture. For audio
 	  capture, you need to select the snd-usb-audio driver (i.e.
 	  CONFIG_SND_USB_AUDIO).
-
-config VIDEO_STK1160
-	tristate
-	depends on VIDEO_STK1160_COMMON
-	default y
-	select VIDEOBUF2_VMALLOC
-	select VIDEO_SAA711X