arch: re-order the entries in the float choice

Re-order the three entries in the float choice, in a more sensible
order, ie:
- all hard-float options come first, then soft-float
- options that use the FPU are marked so: hard and softfp
- options that do not use the FPU are marked so: software

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

 CT_LOCAL_TARBALLS_DIR="${HOME}/src"

 CT_SAVE_TARBALLS=y

 CT_LOG_EXTRA=y

 CT_ARCH_FLOAT_SW=y

 CT_ARCH_arm=y

 CT_BINUTILS_V_2_19_1a=y

 CT_CC_V_4_3_4=y

 CT_CC_LANG_CXX=y

 CT_DEBUG_gdb=y

 CT_GMP_V_4_3_2=y

 CT_MPFR_V_2_4_2=y