scripts/spelling: add a few more typos

Add a few more typos that found from real patches[1,2] to 'spelling' file.

[1] https://lore.kernel.org/linux-mm/[e-mail]/
[2] https://lore.kernel.org/damon/[e-mail]/

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: SeongJae Park <[e-mail]>
Acked-by: Randy Dunlap <[e-mail]>
Cc: Colin Ian King <[e-mail]>
Cc: Drew Fustini <[e-mail]>
Cc: Joe Perches <[e-mail]>
Cc: SeongJae Park <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

scripts/spelling.txt

···
 feautures||features
 fetaure||feature
 fetaures||features
+fetcing||fetching
 fileystem||filesystem
 fimrware||firmware
 fimware||firmware
 firmare||firmware
 firmaware||firmware
+firtly||firstly
 firware||firmware
 firwmare||firmware
 finanize||finalize
···
 ture||true
 tyep||type
 udpate||update
+updtes||updates
 uesd||used
 unknwon||unknown
 uknown||unknown