sh64: Drop deprecated ISA tuning for legacy toolchains.
The original sh64 toolchains required that we tune the ISA level accordingly to not have head.S/entry.S blow up. With current toolchains, this is no longer the case, and the syntax magically changed as well, causing all current toolchains to die a horrible death. Incidentally, code generation in other parts of the kernel is now significantly complex enough that none of the older toolchains make it very far these days, so there's not even any point in preserving legacy compatability via as-option. This fixes a long-standing issue, as noted here: http://lkml.org/lkml/2005/1/5/223 Though at the time the current toolchains were too broken to make adjusting the tuning worthwhile. Signed-off-by: Paul Mundt <firstname.lastname@example.org>