config.gcc (mips64*-*-linux*): Set the default abi to n32.

config.gcc (mips64*-*-linux*): Set the default abi to n32.

	* config.gcc (mips64*-*-linux*): Set the default abi to n32.  Remove
	redundant target_cpu_default and extra_parts lines.  Use the default
	"from-abi" ISA.
	* config/mips/linux64.h (DRIVER_DEFAULT_ABI_SELF_SPEC): Delete.
	(SUBTARGET_EXTRA_SPECS): Delete.
	(DRIVER_SELF_SPECS): Remove architecture lines.  Set the ABI directly.
	(SUBTARGET_ASM_SPEC): Remove -mabi=n32 and -mabi=64 mappings.
	* config/mips/t-linux64 (MULTILIB_DIRNAMES): Use "32" for -mabi=32
	and "n32" for -mabi=n32.

From-SVN: r93777