arch/sparc: drop old SUN-specific variants

Drop the old Sun-specific variants used in old workstations (pre-1997)
and other useless ones.

The V7 ISA is a very old cpu only used in the first Sun workstations,
the toolchain support is broken: the cpu doesn't do hardware div and
it's not handled elsewhere.

The sparclite is also a very old Fujitsu cpu only used in early 90s Sun
machines (includes f930 & f934).

The sparclet (tsc701) was a microcontroller-variant.

The supersparc and hypersparc are just V8 variants also used in old Sun
workstations/servers.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>