Need to ensure that reg_output is not updated while setting multiple
bits. This makes the mutex locking behaviour for the set_multiple call
consistent with that of the set_value call.
Cc: stable@vger.kernel.org
Fixes: b4818afeacbd ("gpio: pca953x: Add set_multiple to allow multiple") Signed-off-by: Phil Reid <preid@electromag.com.au> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>