arch/arm: ARM supports the softfp convention

ARM compilers can be built for soft float (software only, floats in
core registers), hard float (uses floating point instructions, floats
in FPU registers), or the half-way house softfp (uses floating point
instructions, floats in core registers).

Signed-off-by: Michael Hope <michael.hope@linaro.org>
[yann.morin.1998@anciens.enib.fr: split the original patch]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

     1.1 --- a/config/arch/arm.in	Wed Oct 19 15:27:32 2011 +1300
     1.2 +++ b/config/arch/arm.in	Wed Oct 19 15:27:32 2011 +1300
     1.3 @@ -10,6 +10,7 @@
     1.4  ## select ARCH_SUPPORT_CPU
     1.5  ## select ARCH_SUPPORT_TUNE
     1.6  ## select ARCH_SUPPORT_FPU
     1.7 +## select ARCH_SUPPORT_SOFTFP
     1.8  ##
     1.9  ## help The ARM architecture, as defined by:
    1.10  ## help     http://www.arm.com/