net: dsa: rzn1-a5psw: Remove redundant of_match_ptr()

The driver depends on CONFIG_OF, it is not necessary to use
of_match_ptr() here.

Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>