arch/arm: add option to use *eabihf tuples

Toolchains that use the hard-float ABI now are to be denoted by a tuple
ending in *eabihf, while the prevbious *eabi is now an indication that
the toolchain uses the softfloat ABI.

This is purely a cosmetic thing, for distros to differentiate their
hardfloat-ABI ports from their softfloat-ABI ports.

(note: softfloat ABI does not mean that it is using softfloats; it can
be using hardfloat instructions, but using the softfloat ABI).

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

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 CT_LOCAL_TARBALLS_DIR="${HOME}/src"

 CT_SAVE_TARBALLS=y

 CT_LOG_EXTRA=y

 CT_ARCH_s390=y

 CT_KERNEL_linux=y

 CT_KERNEL_V_2_6_31_14=y

 CT_BINUTILS_V_2_20_1a=y

 CT_CC_V_4_3_4=y

 CT_CC_LANG_CXX=y

 CT_LIBC_glibc=y

 CT_LIBC_GLIBC_V_2_9=y

 CT_GMP_V_4_3_2=y

 CT_MPFR_V_2_4_2=y