hwmon: (lis3lv02d) Prevent NULL pointer dereference

If CONFIG_PM was selected and lis3lv02d_platform_data was NULL,
the kernel will be panic when halt command run.

Reported-by: Yusuke Goda <yusuke.goda.sx@renesas.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Samu Onkalo <samu.p.onkalo@nokia.com>
Sigend-off-by: Jean Delvare <khali@linux-fr.org>