Use libc calls defined by fenv_private.h to implement several fenv functions

Use libc calls defined by fenv_private.h to implement several fenv functions
rather than duplicating functionality. To make this work for softfp builds,
ensure functions in fenv_private are not conditionally compiled.

2014-06-24  Wilco  <wdijkstr@arm.com>

	* sysdeps/arm/fegetround.c (fegetround): Call get_rounding_mode.
	* sysdeps/arm/feholdexcpt.c (feholdexcept): Call libc_feholdexcept_vfp.
	* sysdeps/arm/fesetround.c (fesetround): Call libc_fesetround_vfp.
	* sysdeps/arm/fgetexcptflg.c (fegetexceptflag):
	Call libc_fetestexcept_vfp.
	* sysdeps/arm/ftestexcept.c (fetestexcept): Call libc_fetestexcept_vfp.
	* sysdeps/arm/fenv_private.h: Move libc_*_vfp functions outside of
	__SOFTFP__ ifdef so that they can be built for softfp.