Convert the various uses of fallthrough comments to fallthrough;

Done via script
Link: https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe@perches.com/Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # for the I2C part
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>