m68kemb.h (TARGET_OS_CPP_BUILTINS): Remove redundant definition of mc68000, already present in TARGET_CPU_CPP_BUILTINS.

	* config/m68k/m68kemb.h (TARGET_OS_CPP_BUILTINS): Remove redundant
	definition of mc68000, already present in TARGET_CPU_CPP_BUILTINS.

From-SVN: r92384