drivers/net: delete old 8 bit ISA Racal ni5010 support.

These cards were only available in 8bit format, and in addition
they only had AUI and BNC(10-Base2) interfaces (i.e. no RJ-45).

In fact, they are so rare, that an internet search on these old
cards almost comes up empty, unless the "Micom interlan" name
is used.

This puts them in the equivalent domain as the 3c501, so there
should be no strong opposition to the driver removal, as nobody
is seriously using 3.9+ with 8 bit ISA hardware.

In doing so, the whole "ethernet/racal" category becomes empty,
so we clean up the Makefile/Kconfig and subdir appropriately.

Cc: Andreas Mohr <andi@lisas.de>
Cc: Jan-Pascal van Best <janpascal@vanbest.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>