Documentation: USB: correct possessive "its" usage

Correct uses of "it's" to possessive "its" or "its" to "it's" as needed.
Correct associated grammar in one location.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Link: https://lore.kernel.org/r/20221118231422.14076-1-rdunlap@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/usb/CREDITS

@@ -1,7 +1,7 @@
 Credits for the Simple Linux USB Driver:
 
 The following people have contributed to this code (in alphabetical
-order by last name).  I'm sure this list should be longer, its
+order by last name).  I'm sure this list should be longer, it's
 difficult to maintain, add yourself with a patch if desired.
 
   Georg Acher <acher@informatik.tu-muenchen.de>
@@ -126,7 +126,7 @@ THANKS file in Inaky's driver):
         - Jochen Karrer <karrer@wpfd25.physik.uni-wuerzburg.de>, for
           pointing out mortal bugs and giving advice.
 
-        - Edmund Humemberger <ed@atnet.at>, for it's great work on
+        - Edmund Humemberger <ed@atnet.at>, for his great work on
           public relationships and general management stuff for the
           Linux-USB effort.
 
@@ -136,7 +136,7 @@ THANKS file in Inaky's driver):
         - Ric Klaren <ia_ric@cs.utwente.nl> for doing nice
           introductory documents (competing with Alberto's :).
 
-        - Christian Groessler <cpg@aladdin.de>, for it's help on those
+        - Christian Groessler <cpg@aladdin.de>, for his help on those
           itchy bits ... :)
 
         - Paul MacKerras for polishing OHCI and pushing me harder for

Documentation/usb/functionfs.rst

@@ -49,7 +49,7 @@ level it would look like this::
   $ ( cd /dev/ffs-hid && hid-daemon ) &
 
 On kernel level the gadget checks ffs_data->dev_name to identify
-whether it's FunctionFS designed for MTP ("mtp") or HID ("hid").
+whether its FunctionFS is designed for MTP ("mtp") or HID ("hid").
 
 If no "functions" module parameters is supplied, the driver accepts
 just one function with any name.

Documentation/usb/gadget_multi.rst

@@ -9,7 +9,7 @@ The Multifunction Composite Gadget (or g_multi) is a composite gadget
 that makes extensive use of the composite framework to provide
 a... multifunction gadget.
 
-In it's standard configuration it provides a single USB configuration
+In its standard configuration it provides a single USB configuration
 with RNDIS[1] (that is Ethernet), USB CDC[2] ACM (that is serial) and
 USB Mass Storage functions.