clk: gate: fix comment typo and grammar

Change ouput -> output.

While at it change also grammatically incorrect "it's" to "its".

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Link: https://lore.kernel.org/r/d47978a09dd0320f9929a19fa3e829608a02b224.1693485415.git.baruch@tkos.co.il


Signed-off-by: Stephen Boyd <sboyd@kernel.org>