net/smc9194: Remove bogus CONFIG_MAC reference

AFAIK the only version of smc9194.c with Mac support is the one in the
linux-mac68k CVS repo, which never made it to the mainline.

Despite that, from v2.3.45, arch/m68k/config.in listed CONFIG_SMC9194
under CONFIG_MAC. This mistake got carried over into Kconfig in v2.5.55.
(See pre-git era "[PATCH] add m68k dependencies to net driver config".)

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>