[arm] Make 'auto' the default FPU selection option.

[arm] Make 'auto' the default FPU selection option.

Finally, we can make 'auto' the default choice for the FPU option.  It's
still possible to override this during configure, but we will eventually
deprecate that, moving to the new cpu/architecture selection mechanism.

	* config/arm/arm.h (FPUTYPE_AUTO): Define.
	* config/arm/arm.c (arm_option_override): Use FPUTYPE_AUTO if the
	fpu is not specified by the user/command-line.
	* config/arm/bpabi.h (FPUTYPE_DEFAULT): Delete.
	* config/arm/netbsd-elf.h (FPUTYPE_DEFAULT): Delete.
	* config/arm/linux-elf.h (FPUTYPE_DEFAULT): Delete.
	* config/arm/vxworks.h (FPUTYPE_DEFAULT): Delete.
	* common/config/arm/arm-common.c (arm_canon_arch_option): Use
	FPUTYPE_AUTO insted of FPUTYPE_DEFAULT.

From-SVN: r249295