usb: pd: Update some sysfs entries to return hex values

Update several of the PD 3.0 related sysfs entries to return a
hexadecimal string of the byte data returned instead of decimal.
For the messages that correspond to non-extended messages, these
data objects should be printed as '0x1234ABCD' to ease human
translation to binary. For extended messages the payloads contain
fields of single or multi-byte values, so it's easiest to return
a string of hex bytes.

Change-Id: I436e90d9b5b472362ae39050dd775363db46207c
Signed-off-by: Jack Pham <jackp@codeaurora.org>