msm: fix incorrect termination of struct of_device_id arrays

qpnp-power-on.c and qpnp-usbdetect.c didn't correctly NULL-terminate
their devicetree match tables. This would result in of_dev_lookup()
running off the end of the array and looking at bogus data. Now fix
this kind of incorrect termination.

CRs-fixed: 582126
Change-Id: I44e9742af78614bd630e7d3e95dbf9f6bffc8955
Signed-off-by: Xu Kai <kaixu@codeaurora.org>