kernel/linux: change m68k/no-mmu linux arch tuple to use -uclinux

GCC requires m68k arch tuples to be *-*-uclinux-* to support Linux on
no-mmu m68k (ColdFire) cpus.

Blackfin arch tuple must be *-*-linux-uclibc for FD_PIC_ELF toolchains,
so we cannot just switch to uclinux for no-mmu Linux toolchains.

Signed-off-by: "Esben Haabendal" <esben@haabendal.dk>
Message-Id: <876271s1ee.fsf@arh128.prevas.dk>
PatchWork-Id: 186976

 source "config/configure.in"

 source "config/backend.in"

 source "config/global.in"

 source "config/target.in"

 source "config/toolchain.in"

 source "config/kernel.in"

 source "config/binutils.in"

 source "config/cc.in"

 source "config/libc.in"

 source "config/debug.in"

 source "config/companion_libs.in"

 source "config/companion_tools.in"

 source "config/test_suite.in"