sepolicy : Correcting path regexp in file_context for sysfs_usbpd_device

As it was assumed that all the node path of pmic and usb are going
to have hex values in the path where [a-z0-9] was replace with
[a-f0-9] which was leading to regression  so correcting them.

Change-Id: I9f3f60e3d68662e9286191965f232625f5dd4bd2