Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>

Documentation/serial/moxa-smartio

@@ -473,7 +473,7 @@ Content
    spd_normal	  Use  38.4kb  when  the application requests 38.4kb.
    spd_cust	  Use  the custom divisor to set the speed when  the
 		  application requests 38.4kb.
-   divisor	  This option set the custom divison.
+   divisor	  This option set the custom division.
    baud_base	  This option set the base baud rate.
 
 -----------------------------------------------------------------------------