ds2781_battery: Replace call to kzalloc with devm_kzalloc
ds2781_battery: Replace call to kzalloc with devm_kzalloc

With devm_kzalloc there is no need of freeing at the errorpath and also
at unregister it.

Signed-off-by: Devendra Naga <80be44de42a8601c5f7021eac61c2116586290ae@gmail.com>
Signed-off-by: Anton Vorontsov <1aae5ab9541d66245293c8fc1b9880f5df073631@linaro.org>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas