net: sh_eth: Use u32 for 32-bit register data

Replace "unsigned long" by "u32" when handling 32-bit register data.

A.o., this saves 11 * 36 bytes in the static sh_eth_cpu_data structures
when compiling for 64-bit.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: David S. Miller <davem@davemloft.net>