hwmon: pmbus: ucd9000: remove unneeded include

Build bot reports the following build issue after commit 9091373a
("gpio: remove less important #ifdef around declarations):

   In file included from drivers/hwmon/pmbus/ucd9000.c:19:0:
>> include/linux/gpio/driver.h:576:1: error: redefinition of 'gpiochip_add_pin_range'
    gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
    ^~~~~~~~~~~~~~~~~~~~~~
   In file included from drivers/hwmon/pmbus/ucd9000.c:18:0:
   include/linux/gpio.h:245:1: note: previous definition of 'gpiochip_add_pin_range' was here
    gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
    ^~~~~~~~~~~~~~~~~~~~~~
   In file included from drivers/hwmon/pmbus/ucd9000.c:19:0:
>> include/linux/gpio/driver.h:583:1: error: redefinition of 'gpiochip_add_pingroup_range'
    gpiochip_add_pingroup_range(struct gpio_chip *chip,
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   In file included from drivers/hwmon/pmbus/ucd9000.c:18:0:
   include/linux/gpio.h:254:1: note: previous definition of 'gpiochip_add_pingroup_range' was here
    gpiochip_add_pingroup_range(struct gpio_chip *chip,
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   In file included from drivers/hwmon/pmbus/ucd9000.c:19:0:
>> include/linux/gpio/driver.h:591:1: error: redefinition of 'gpiochip_remove_pin_ranges'
    gpiochip_remove_pin_ranges(struct gpio_chip *chip)
    ^~~~~~~~~~~~~~~~~~~~~~~~~~
   In file included from drivers/hwmon/pmbus/ucd9000.c:18:0:
   include/linux/gpio.h:263:1: note: previous definition of 'gpiochip_remove_pin_ranges' was here
    gpiochip_remove_pin_ranges(struct gpio_chip *chip)

This is caused by conflicting defines from linux/gpio.h and
linux/gpio/driver.h. Drivers should not include both the legacy and
the new API headers. This driver doesn't even use linux/gpio.h so
remove it.
Reported-by: kbuild test robot <lkp@intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Link: https://lore.kernel.org/r/20190808080144.6183-1-brgl@bgdev.plSigned-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/pmbus/ucd9000.c

@@ -15,7 +15,6 @@
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/pmbus.h>
-#include <linux/gpio.h>
 #include <linux/gpio/driver.h>
 #include "pmbus.h"