media: v4l2-core: Fix kernel-doc markups

media: v4l2-core: Fix kernel-doc markups

There are some troubles on kernel-doc markups, as warned:

	drivers/media/v4l2-core/v4l2-dv-timings.c:259: warning: No description found for parameter 't1'
	drivers/media/v4l2-core/v4l2-dv-timings.c:259: warning: No description found for parameter 't2'
	drivers/media/v4l2-core/v4l2-dv-timings.c:259: warning: No description found for parameter 'pclock_delta'
	drivers/media/v4l2-core/v4l2-dv-timings.c:259: warning: No description found for parameter 'match_reduced_fps'
	drivers/media/v4l2-core/tuner-core.c:242: warning: bad line: internal parameters, like LNA mode
	drivers/media/v4l2-core/tuner-core.c:765: warning: No description found for parameter 'mode'
	drivers/media/v4l2-core/videobuf2-memops.c:127: warning: cannot understand function prototype: 'const struct vm_operations_struct vb2_common_vm_ops = '
	drivers/media/v4l2-core/v4l2-mem2mem.c:190: warning: No description found for parameter 'm2m_dev'
	drivers/media/v4l2-core/v4l2-mem2mem.c:291: warning: No description found for parameter 'm2m_ctx'
	drivers/media/v4l2-core/videobuf-core.c:233: warning: No description found for parameter 'q'

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>