V4L/DVB: tm6000: Fix warnings due to a small array size

drivers/staging/tm6000/tm6000-stds.c:101: warning: excess elements in array initializer
drivers/staging/tm6000/tm6000-stds.c:101: warning: (near initialization for ‘tv_stds[0].common’)
drivers/staging/tm6000/tm6000-stds.c:160: warning: excess elements in array initializer
drivers/staging/tm6000/tm6000-stds.c:160: warning: (near initialization for ‘tv_stds[1].common’)
drivers/staging/tm6000/tm6000-stds.c:219: warning: excess elements in array initializer
drivers/staging/tm6000/tm6000-stds.c:219: warning: (near initialization for ‘tv_stds[2].common’)
drivers/staging/tm6000/tm6000-stds.c:336: warning: excess elements in array initializer
drivers/staging/tm6000/tm6000-stds.c:336: warning: (near initialization for ‘tv_stds[4].common’)

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