media: netup_unidvb: fix a bad kernel-doc markup

There is a bad kernel-doc markup, producing the following warnings:

  drivers/media/pci/netup_unidvb/netup_unidvb_core.c:85: warning: bad line: 			Bits [0-7]:	DMA packet size, 188 bytes
  drivers/media/pci/netup_unidvb/netup_unidvb_core.c:86: warning: bad line: 			Bits [16-23]:	packets count in block, 128 packets
  drivers/media/pci/netup_unidvb/netup_unidvb_core.c:87: warning: bad line: 			Bits [24-31]:	blocks count, 8 blocks
  drivers/media/pci/netup_unidvb/netup_unidvb_core.c:89: warning: bad line: 			For example, value of 375000000 equals to 3 sec

Fix that, and use a list for the bits option, in order for it
to be better format, if we add it to a driver's documentation
file.

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