gpiolib: add gpiod_multi_set_value_cansleep()

Add a new gpiod_multi_set_value_cansleep() helper function with fewer
parameters than gpiod_set_array_value_cansleep().

Calling gpiod_set_array_value_cansleep() can get quite verbose. In many
cases, the first arguments all come from the same struct gpio_descs, so
having a separate function where we can just pass that cuts down on the
boilerplate.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20250210-gpio-set-array-helper-v3-1-d6a673674da8@baylibre.com


Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>