configure: fix dependencies for v4l2_indev

There's no indev named libv4l2.

Fixes ticket #6729

Reviewed-by: bermond
Signed-off-by: James Almer <jamrial@gmail.com>

configure

@@ -3116,7 +3116,7 @@ kmsgrab_indev_deps="libdrm"
 lavfi_indev_deps="avfilter"
 libcdio_indev_deps="libcdio"
 libdc1394_indev_deps="libdc1394"
-libv4l2_indev_deps="libv4l2"
+v4l2_indev_deps="libv4l2"
 openal_indev_deps="openal"
 opengl_outdev_deps="opengl"
 oss_indev_deps_any="soundcard_h sys_soundcard_h"