octeon_ep_vf: Improve help text grammar

Add missing articles.
Fix plural vs. singular.
Fix present vs. future.

Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Sathesh B Edara <sedara@marvell.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/b3b97462c3d9eba2ec03dd6d597e63bf49a7365a.1708512706.git.geert+renesas@glider.be


Signed-off-by: Jakub Kicinski <kuba@kernel.org>