sh_eth: Add support for r8a7790 SoC

This is a copy of support for r8a7778/9 with the .rmiimode mode bit
of struct sh_eth_cpu_data set.

Also update R8A7779 to R8A777x.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/renesas/Kconfig

@@ -13,4 +13,4 @@ config SH_ETH
 	  Renesas SuperH Ethernet device driver.
 	  This driver supporting CPUs are:
 		- SH7619, SH7710, SH7712, SH7724, SH7734, SH7763, SH7757,
-		  R8A7740 and R8A7779.
+		  R8A7740, R8A777x and R8A7790.