remove duplicate code

[Kevin Lo]

ok?

Index: sys/dev/usb/if_axe.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/if_axe.c,v
retrieving revision 1.138
diff -u -p -u -p -r1.138 if_axe.c
--- sys/dev/usb/if_axe.c        22 Jan 2017 10:17:39 -0000      1.138
+++ sys/dev/usb/if_axe.c        5 Jul 2019 05:56:19 -0000
@@ -881,10 +881,6 @@ axe_detach(struct device *self, int flag
                    sc->axe_dev.dv_xname);
 #endif
 
-       if (--sc->axe_refcnt >= 0) {
-               /* Wait for processes to go away. */
-               usb_detach_wait(&sc->axe_dev);
-       }
        splx(s);
 
        return (0);
Index: sys/dev/usb/if_axen.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/if_axen.c,v
retrieving revision 1.26
diff -u -p -u -p -r1.26 if_axen.c
--- sys/dev/usb/if_axen.c       5 Dec 2018 15:54:58 -0000       1.26
+++ sys/dev/usb/if_axen.c       5 Jul 2019 05:56:19 -0000
@@ -778,10 +778,6 @@ axen_detach(struct device *self, int fla
                    sc->axen_dev.dv_xname);
 #endif
 
-       if (--sc->axen_refcnt >= 0) {
-               /* Wait for processes to go away. */
-               usb_detach_wait(&sc->axen_dev);
-       }
        splx(s);
 
        return 0;
Index: sys/dev/usb/if_mos.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/if_mos.c,v
retrieving revision 1.39
diff -u -p -u -p -r1.39 if_mos.c
--- sys/dev/usb/if_mos.c        3 Jul 2018 00:47:49 -0000       1.39
+++ sys/dev/usb/if_mos.c        5 Jul 2019 05:56:19 -0000
@@ -784,10 +784,6 @@ mos_detach(struct device *self, int flag
                    sc->mos_dev.dv_xname);
 #endif
 
-       if (--sc->mos_refcnt >= 0) {
-               /* Wait for processes to go away. */
-               usb_detach_wait(&sc->mos_dev);
-       }
        splx(s);
 
        return (0);
Index: sys/dev/usb/if_mue.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/if_mue.c,v
retrieving revision 1.5
diff -u -p -u -p -r1.5 if_mue.c
--- sys/dev/usb/if_mue.c        19 Sep 2018 07:47:54 -0000      1.5
+++ sys/dev/usb/if_mue.c        5 Jul 2019 05:56:19 -0000
@@ -855,10 +855,6 @@ mue_detach(struct device *self, int flag
                if_detach(ifp);
        }
 
-       if (--sc->mue_refcnt >= 0) {
-               /* Wait for processes to go away. */
-               usb_detach_wait(&sc->mue_dev);
-       }
        splx(s);
 
        return (0);
Index: sys/dev/usb/if_smsc.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/if_smsc.c,v
retrieving revision 1.32
diff -u -p -u -p -r1.32 if_smsc.c
--- sys/dev/usb/if_smsc.c       25 Aug 2018 17:09:40 -0000      1.32
+++ sys/dev/usb/if_smsc.c       5 Jul 2019 05:56:19 -0000
@@ -1118,10 +1118,6 @@ smsc_detach(struct device *self, int fla
                    sc->sc_dev.dv_xname);
 #endif
 
-       if (--sc->sc_refcnt >= 0) {
-               /* Wait for processes to go away. */
-               usb_detach_wait(&sc->sc_dev);
-       }
        splx(s);
 
        return (0);