hn: fix build on !x86

hv_netvm aren't installed on !x64. Do the canonical thing with the
links.

Fixes: 83e93d53f6
Sponsored by: Netflix

share/man/man4/Makefile

@@ -713,8 +713,8 @@ MLINKS+=gpioths.4 dht11.4
 MLINKS+=gpioths.4 dht22.4
 MLINKS+=gre.4 if_gre.4
 MLINKS+=hpet.4 acpi_hpet.4
-MLINKS+=hv_netvsc.4 hn.4 \
-	hv_netvsc.4 if_hn.4
+MLINKS+=${_hv_netvsc.4} ${_hn.4} \
+	${_hv_netvsc.4} ${_if_hn.4}
 MLINKS+=${_hptrr.4} ${_rr232x.4}
 MLINKS+=${_attimer.4} ${_i8254.4}
 MLINKS+=ip.4 rawip.4
@@ -838,6 +838,7 @@ _cpuctl.4=	cpuctl.4
 _dpms.4=	dpms.4
 _ftgpio.4=	ftgpio.4
 _ftwd.4=	ftwd.4
+_hn.4=		_hn.4
 _hpt27xx.4=	hpt27xx.4
 _hptiop.4=	hptiop.4
 _hptmv.4=	hptmv.4
@@ -853,6 +854,7 @@ _hwpstate_intel.4=	hwpstate_intel.4
 _i8254.4=	i8254.4
 _ichwd.4=	ichwd.4
 _if_bxe.4=	if_bxe.4
+_if_hn.4=	if_hn.4
 _if_nfe.4=	if_nfe.4
 _if_urtw.4=	if_urtw.4
 _if_vmx.4=	if_vmx.4