[media] samples: v4l: from Documentation to samples directory

With the new autoksyms support, we can run into a situation where
the v4l pci skeleton module is the only one using some exported
symbols that get dropped because they are never referenced by
the kernel otherwise, causing a build problem:

ERROR: "vb2_dma_contig_memops" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!
ERROR: "vb2_dma_contig_init_ctx_attrs" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!
ERROR: "v4l2_match_dv_timings" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!
ERROR: "v4l2_find_dv_timings_cap" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!
ERROR: "v4l2_valid_dv_timings" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!
ERROR: "v4l2_enum_dv_timings_cap" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!
ERROR: "vb2_dma_contig_cleanup_ctx" [Documentation/video4linux/v4l2-pci-skeleton.ko] undefined!

Specifically, we do look in the samples directory for users of
symbols, but not the Documentation directory.

This solves the build problem by moving the connector sample into
the same directory as the other samples.

Fixes: 23121ca2 ("kbuild: create/adjust generated/autoksyms.h")

Signed-off-by: Arnd Bergmann <arnd@arndb.de>