net: altera_tse: get numbers of fdt address and size cells

Get numbers of fdt address and size cells in altera_tse_probe(),
thereby remove the assumption of one address cell and one size
cell.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>