doc: Apply it's/its grammar pedantry

doc/source/additional_topics.rst

@@ -6,10 +6,10 @@ Modules
 
 Modules are essentially plug-ins for Extensions. They provide a way of defining 
 common and reusable functionality. An Extension can load zero or more modules
-during it's creation. Loaded modules will then add their capabilities (see
+during its creation. Loaded modules will then add their capabilities (see
 Capabilities_) to those of the Extension. When calling code tries to access an
 attribute of an Extension the Extension doesn't have, it will try to find the
-attribute among it's loaded modules and will return that instead. 
+attribute among its loaded modules and will return that instead.
 
 .. note:: Modules are themselves extensions, and can therefore load their own
           modules. *Do not* abuse this.

doc/source/device_setup.rst

@@ -64,7 +64,7 @@ you might want to change are outlined below.
    advanced WA functionality (like setting of core-related runtime parameters
    such as governors, frequencies, etc). ``core_names`` should be a list of
    core names matching the order in which they are exposed in sysfs. For
-   example, ARM TC2 SoC is a 2x3 big.LITTLE system; it's core_names would be
+   example, ARM TC2 SoC is a 2x3 big.LITTLE system; its core_names would be
    ``['a7', 'a7', 'a7', 'a15', 'a15']``, indicating that cpu0-cpu2 in cpufreq
    sysfs structure are A7's and cpu3 and cpu4 are A15's.
 

doc/source/writing_extensions.rst

@@ -11,7 +11,7 @@ interesting of these are
             can be benchmarks, high-level use cases, or pretty much anything else.
 :devices: These are interfaces to the physical devices (development boards or end-user
           devices, such as smartphones) that use cases run on. Typically each model of a
-          physical device would require it's own interface class (though some functionality
+          physical device would require its own interface class (though some functionality
           may be reused by subclassing from an existing base).
 :instruments: Instruments allow collecting additional data from workload execution (e.g.
               system traces). Instruments are not specific to a particular Workload. Instruments