The implementation of lp3943_gpio_request/lp3943_gpio_free test pin_used
for tracing the pin usage. However, gpiolib already checks FLAG_REQUESTED
flag for the same purpose. So remove the redundant implementation.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>