In max17042_get_property(...), the values returned by
max17042_read_reg are directly assigned to the variables,
even if the read results in an error.

This patch checks for the return code from max17042_read_reg and
exits the function if there is any error.
Signed-off-by: NRamakrishna Pallala <ramakrishna.pallala@intel.com>
Acked-by: NMyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: NAnton Vorontsov <cbouatmailru@gmail.com>