ARM: disallow pre-ARMv5 builds with ld.lld

lld cannot build for ARMv4/v4T targets because it inserts 'blx' instructions
that are unsupported there:

  ld.lld: warning: lld uses blx instruction, no object with architecture supporting feature detected

Add a Kconfig time dependency to prevent those targets from being
selected in randconfig builds.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://github.com/llvm/llvm-project/issues/50764
Link: https://github.com/ClangBuiltLinux/linux/issues/964
Link: https://lore.kernel.org/r/20221215162635.3750763-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>