arm: rename FPU_ARCH_VFP to FPU_ARCH_SOFTVFP

FPU_ARCH_VFP has always meant VFP floating-point format (natural FP
word order) but without any VFP instructions.  But the name
FPU_ARCH_VFP is potentially confusing.  This patch just changes the
name to make the meaning clearer.
6 files changed