multipath: require kpartx binary

multipath requires kpartx to activate device mapper.
But kpartx is only a recommend dependency.

Check for kpartx's existent first.

Signed-off-by: Doan Tran Cong Danh <congdanhqx@gmail.com>

modules.d/90multipath/module-setup.sh

@@ -29,6 +29,7 @@ check() {
 
     # if there's no multipath binary, no go.
     require_binaries multipath || return 1
+    require_binaries kpartx || return 1
 
     return 0
 }