Documentation: Fix spelling mistakes

Corrected a few spelling mistakes to improve the readability.

Signed-off-by: Ranganath V N <[e-mail]>
Acked-by: Rob Herring (Arm) <[e-mail]>
Reviewed-by: Randy Dunlap <[e-mail]>
Signed-off-by: Jonathan Corbet <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

Documentation/devicetree/bindings/submitting-patches.rst

···
      any DTS patches, regardless whether using existing or new bindings, should
      be placed at the end of patchset to indicate no dependency of drivers on
      the DTS.  DTS will be anyway applied through separate tree or branch, so
-     different order would indicate the serie is non-bisectable.
+     different order would indicate the series is non-bisectable.
 
      If a driver subsystem maintainer prefers to apply entire set, instead of
      their relevant portion of patchset, please split the DTS patches into

Documentation/filesystems/iomap/operations.rst

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   - ``writeback_submit``: Submit the previous built writeback context.
     Block based file systems should use the iomap_ioend_writeback_submit
     helper, other file system can implement their own.
-    File systems can optionall to hook into writeback bio submission.
+    File systems can optionally hook into writeback bio submission.
     This might include pre-write space accounting updates, or installing
     a custom ``->bi_end_io`` function for internal purposes, such as
     deferring the ioend completion to a workqueue to run metadata update

Documentation/virt/kvm/review-checklist.rst

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   It is important to demonstrate your use case.  This can be as simple as
   explaining that the feature is already in use on bare metal, or it can be
   a proof-of-concept implementation in userspace.  The latter need not be
-  open source, though that is of course preferrable for easier testing.
+  open source, though that is of course preferable for easier testing.
   Selftests should test corner cases of the APIs, and should also cover
   basic host and guest operation if no open source VMM uses the feature.