amd64: -m32 support for machine/profile.h

Install the i386 profile.h under /usr/include/i386 on amd64 and include
when targeting i386.

Reviewed by:	jhb, imp

include/i386/Makefile

@@ -2,7 +2,8 @@
 
 .PATH: ${SRCTOP}/sys/i386/include
 INCS=	\
-	cpufunc.h
+	cpufunc.h \
+	profile.h
 INCSDIR=	${INCLUDEDIR}/i386
 
 .include <bsd.prog.mk>

sys/amd64/include/profile.h

@@ -32,6 +32,10 @@
  * $FreeBSD$
  */
 
+#ifdef __i386__
+#include <i386/profile.h>
+#else /* !__i386__ */
+
 #ifndef _MACHINE_PROFILE_H_
 #define	_MACHINE_PROFILE_H_
 
@@ -116,3 +120,5 @@ __END_DECLS
 #endif /* !_KERNEL */
 
 #endif /* !_MACHINE_PROFILE_H_ */
+
+#endif /* __i386__ */