binutils/binutils: add BINUTILS_2_21_or_later blind option

Add BINUTILS_2_21_or_later blind option. It will be used to add
conditional support for building 'gold' on versions that have it.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

# Alpha specific configuration file

config ARCH_alpha

    select ARCH_SUPPORTS_32

    select ARCH_DEFAULT_32

    select ARCH_USE_MMU

    select ARCH_SUPPORT_CPU

    select ARCH_SUPPORT_TUNE

    help

      The Alpha architecture.