regulator: lp8755: Drop useless header

The lp8755 includes the legacy header <linux/gpio.h> for no
reason, drop the include.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230808-descriptors-regulator-v1-9-939b5e84dd18@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/lp8755.c

@@ -13,7 +13,6 @@
 #include <linux/err.h>
 #include <linux/irq.h>
 #include <linux/interrupt.h>
-#include <linux/gpio.h>
 #include <linux/regmap.h>
 #include <linux/uaccess.h>
 #include <linux/regulator/driver.h>