Install vmx man page also on arm64
Fixes: 375d797b8191 Enable pvscsi and vmx in arm64 GENERIC
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D47711
(cherry picked from commit 4de4f81f379edc5f3a0c0bd1a2325bf8a1873e7e)
(cherry picked from commit 20675c61d1397c3f9f5dc857b0997a1172e05164)