V4L/DVB (13820): lgdt3305: make one-bit bitfields unsigned

Make one-bit bitfields unsigned which will remove the following
sparse warning messages (see "make C=1"):
 * lgdt3305.h:57:21: error: dubious one-bit signed bitfield
 * lgdt3305.h:60:26: error: dubious one-bit signed bitfield
 * lgdt3305.h:63:19: error: dubious one-bit signed bitfield

Signed-off-by: Nemeth Marton <nm127@freemail.hu>
Signed-off-by: Michael Krufky <mkrufky@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>