V4L/DVB (7274): dabusb: fix shadowed variable warning in dabusb.c

drivers/media/video/dabusb.c:208:6: warning: symbol 'buffers' shadows an earlier one
drivers/media/video/dabusb.c:63:12: originally declared here

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>