sh_eth: fix TRSCER mask for R7S9210

According  to the RZ/A2M Group User's Manual: Hardware, Rev. 2.00,
the TRSCER register has bit 9 reserved, hence we can't use the driver's
default TRSCER mask.  Add the explicit initializer for sh_eth_cpu_data::
trscer_err_mask for R7S9210.

Fixes: 6e0bb04d ("sh_eth: Add R7S9210 support")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omprussia.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>