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>

 --- gcc-4.3.4/libffi/src/arm/sysv.S	

 +++ gcc-4.3.4/libffi/src/arm/sysv.S	

 @@ -235,7 +235,7 @@ ARM_FUNC_START ffi_closure_SYSV

  	stmfd	sp!, {ip, lr}

  	UNWIND .save	{r0, lr}

  	add	r2, sp, #8

 -	.pad #16

 +	UNWIND .pad #16

  	sub	sp, sp, #16

  	str	sp, [sp, #8]

  	add	r1, sp, #8