net: mac8390 - Sort out memory/MMIO accesses and casts

commit 5c7fffd0 ("drivers/net/mac8390.c: Remove
useless memcpy casting") removed too many casts, introducing the following
warnings:

| drivers/net/mac8390.c:248: warning: passing argument 1 of '__builtin_memcpy' makes pointer from integer without a cast
| drivers/net/mac8390.c:253: warning: passing argument 1 of 'word_memcpy_tocard' makes pointer from integer without a cast
| drivers/net/mac8390.c:255: warning: passing argument 2 of 'word_memcpy_fromcard' makes pointer from integer without a cast

Instead of just readding the casts,
  - move all casts inside word_memcpy_{to,from}card(),
  - replace an incorrect memcpy() by memcpy_toio(),
  - add memcmp_withio() as a wrapper around memcmp(),
  - replace an incorrect memcpy_toio() by memcpy_fromio().

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>