Fix the following sparse warnings:
 CHECK   drivers/staging/iio/magnetometer/hmc5843_core.c
drivers/staging/iio/magnetometer/hmc5843_core.c:138:70: warning:
incorrect type in argument 3 (different signedness)
drivers/staging/iio/magnetometer/hmc5843_core.c:138:70:    expected
unsigned int *val
drivers/staging/iio/magnetometer/hmc5843_core.c:138:70:    got int
*<noident>
drivers/staging/iio/magnetometer/hmc5843_core.c:215:64: warning:
incorrect type in argument 3 (different signedness)
drivers/staging/iio/magnetometer/hmc5843_core.c:215:64:    expected
unsigned int *val
drivers/staging/iio/magnetometer/hmc5843_core.c:215:64:    got int
*<noident>
drivers/staging/iio/magnetometer/hmc5843_core.c:354:72: warning:
incorrect type in argument 3 (different signedness)
drivers/staging/iio/magnetometer/hmc5843_core.c:354:72:    expected
unsigned int *val
drivers/staging/iio/magnetometer/hmc5843_core.c:354:72:    got int
*<noident>
drivers/staging/iio/magnetometer/hmc5843_core.c:362:72: warning:
incorrect type in argument 3 (different signedness)
drivers/staging/iio/magnetometer/hmc5843_core.c:362:72:    expected
unsigned int *val
drivers/staging/iio/magnetometer/hmc5843_core.c:362:72:    got int
*<noident>
Signed-off-by: Teodora Baluta <teodora.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
 static int hmc5843_wait_measurement(struct hmc5843_data *data)
 {
        int tries = 150;
-       int val;
+       unsigned int val;
        int ret;
 
        while (tries-- > 0) {
                                                char *buf)
 {
        struct hmc5843_data *data = iio_priv(dev_to_iio_dev(dev));
-       int val;
+       unsigned int val;
        int ret;
 
        ret = regmap_read(data->regmap, HMC5843_CONFIG_REG_A, &val);
                            int *val, int *val2, long mask)
 {
        struct hmc5843_data *data = iio_priv(indio_dev);
-       int rval;
+       unsigned int rval;
        int ret;
 
        switch (mask) {