sh_eth: Fix addition of .trscer_err_mask to wrong SoC data

commit b284fbe3 ("sh_eth: Fix access to TRSCER register") wanted
to add a .trscer_err_mask value to the R-Car Gen2 family-specific data
structure (r8a779x_data), but it was accidentally added to the
SH7724-specific data structure (sh7724_data).

Presumably this happened due to a patch conflict with commit
d407bc02 ("sh-eth: Set fdr_value of R-Car SoCs"), which added
another field at the same position.

Move the field setting to fix this.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Fixes: b284fbe3 ("sh_eth: Fix access to TRSCER register")
Signed-off-by: David S. Miller <davem@davemloft.net>