net: skbuff: fix spelling errors

Correct spelling as reported by codespell.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20231213043511.10357-1-rdunlap@infradead.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>