or1k: Add builtin define to detect hard float

This is used in libgcc and now glibc to detect when hardware floating
point operations are supported by the target.

gcc/ChangeLog:

	* config/or1k/or1k.h (TARGET_CPU_CPP_BUILTINS): Add builtin
	  define for __or1k_hard_float__.

gcc/config/or1k/or1k.h

@@ -30,6 +30,8 @@
       builtin_define ("__or1k__");		\
       if (TARGET_CMOV)				\
 	builtin_define ("__or1k_cmov__");	\
+      if (TARGET_HARD_FLOAT)			\
+	builtin_define ("__or1k_hard_float__");	\
       builtin_assert ("cpu=or1k");		\
       builtin_assert ("machine=or1k");		\
     }						\