V4L/DVB: stv0900: dereference of state->internal in fe_stv0900_error stv0900_init_internal()

state->internal allocation may fail as well as the allocation of
stv0900_first_inode or new_node->next_inode in append_internal().

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>